# A revision of the “spiny solanums” of Tropical Asia
(Solanum, the Leptostemonum Clade, Solanaceae)

Xavier Aubriot, Sandra Knapp

► To cite this version:

Xavier Aubriot, Sandra Knapp. A revision of the “spiny solanums” of Tropical Asia (Solanum, the Lep-
tostemonum Clade, Solanaceae). PhytoKeys, 2022, 198, pp.1 - 270. 10.3897/phytokeys.198.79514.
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# A revision of the “spiny solanums” of Tropical Asia (Solanum, the Leptostemonum Clade, Solanaceae)

Xavier Aubriot¹,², Sandra Knapp²

1 Université Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique et Evolution, 91190, Gif-sur-Yvette, France 2 The Natural History Museum, Cromwell Road, London SW7 5BD, UK

Corresponding author: Sandra Knapp (s.knapp@nhm.ac.uk)

Academic editor: Leandro Giacomin | Received 18 December 2021 | Accepted 20 April 2022 | Published 1 June 2022

**Citation:** Aubriot X, Knapp S (2022) A revision of the “spiny solanums” of Tropical Asia (Solanum, the Leptostemonum Clade, Solanaceae). PhytoKeys 198: 1–270. https://doi.org/10.3897/phytokeys.198.79514

## Abstract

The Leptostemonum Clade, or the “spiny solanums”, is the most species-rich monophyletic clade of the large cosmopolitan genus *Solanum* (Solanaceae) and represents almost half the species diversity of the genus. Species diversity in the clade is highest in the Americas, but significant clusters of endemic taxa occur in the Eastern Hemisphere. We present here a taxonomic revision of the 51 species of spiny solanums occurring in tropical Asia (excluding the island of New Guinea, and the lowlands of Nepal and Bhutan). Three species are described as new: *Solanum kachinense* X.Aubriot & S.Knapp, sp. nov. from northern Myanmar, *S. peikuoense* S.S.Ying, sp. nov. from Taiwan, and *S. sulawesi* X.Aubriot & S.Knapp, sp. nov. from northern Sulawesi, Indonesia. Of the spiny solanums occurring in the region, 38 are native and 13 are introduced from the Americas or Africa, either as adventive weeds or as cultivated plants. Phylogenetic resolution amongst these taxa is still a work in progress, so we have chosen to treat these taxa in a geographical context to aid with identification and further taxon discovery. For the native species we provide complete nomenclatural details for all recognised species and their synonyms, complete descriptions, distributions including maps, common names and uses, and preliminary conservation assessments. For the introduced taxa that have been treated in detail elsewhere we provide details of types, synonyms based on tropical Asian material, general distributions, and common names for the region. We provide lecto- or neotypifications for 67 names; 63 for native and 4 for introduced taxa. All taxa are discussed and compared to similar species; keys are provided for all taxa. We illustrate all native species with herbarium and field photographs and introduced species with field photographs only. All specimens examined for this treatment are included in Suppl. materials 1–3 as searchable files.

## Keywords

Asia, endemism, islands, Leptostemonum, spiny solanums, taxonomy, tropical forests, weeds
Table of contents

<table><tr><td>Introduction</td><td>3</td></tr><tr><td>Taxonomic history and phylogeny</td><td>6</td></tr><tr><td>Morphology</td><td>10</td></tr><tr><td>Ecology and natural history</td><td>23</td></tr><tr><td>Uses</td><td>24</td></tr><tr><td>Species concepts</td><td>26</td></tr><tr><td>Materials and methods</td><td>27</td></tr><tr><td>Taxonomic treatment</td><td>29</td></tr><tr><td>Artificial key to tropical Asian spiny solanum species (including non-native adventive taxa)</td><td>31</td></tr><tr><td>Synoptic character list for tropical Asian spiny solanums</td><td>40</td></tr><tr><td>Species descriptions (species with * are introduced, either cultivated and/or naturalised)</td><td>42</td></tr><tr><td>1. Solanum aculeatissimum Jacq. *</td><td>42</td></tr><tr><td>2. Solanum aethiopicum L. *</td><td>43</td></tr><tr><td>3. Solanum arundo Mattei</td><td>45</td></tr><tr><td>4. Solanum barbisetum Nees</td><td>48</td></tr><tr><td>5. Solanum camranhense Dy Phon & Hul.</td><td>52</td></tr><tr><td>6. Solanum capsicoides All. *</td><td>55</td></tr><tr><td>7. Solanum chrysotrichum Schltdl. *</td><td>56</td></tr><tr><td>8. Solanum comitis Dunal</td><td>57</td></tr><tr><td>9. Solanum cordatum Forssk.</td><td>61</td></tr><tr><td>10. Solanum cyanocarphium Blume</td><td>64</td></tr><tr><td>11. Solanum deflexicarpum C.Y.Wu & S.C.Huang</td><td>69</td></tr><tr><td>12. Solanum dunalianum Gaudich.</td><td>72</td></tr><tr><td>13. Solanum elaeagnifolium Cav. *</td><td>77</td></tr><tr><td>14. Solanum forskalii Dunal</td><td>77</td></tr><tr><td>15. Solanum giganteum Jacq.</td><td>81</td></tr><tr><td>16. Solanum graciliflorum Dunal</td><td>85</td></tr><tr><td>17. Solanum harmandii Bonati</td><td>89</td></tr><tr><td>18. Solanum hovei Dunal</td><td>92</td></tr><tr><td>19. Solanum insanum L.</td><td>95</td></tr><tr><td>20. Solanum involucratum Blume</td><td>102</td></tr><tr><td>21. Solanum jamaicense Mill. *</td><td>106</td></tr><tr><td>22. Solanum kachinense X.Aubriot & S.Knapp, sp. nov.</td><td>107</td></tr><tr><td>23. Solanum lasiocarpum Dunal</td><td>111</td></tr><tr><td>24. Solanum macrocarpon L. *</td><td>116</td></tr><tr><td>25. Solanum mammosum L. *</td><td>117</td></tr><tr><td>26. Solanum melongena L.</td><td>119</td></tr><tr><td>27. Solanum miyakojimense T.Yamaz. & Takushi</td><td>129</td></tr></table>
<table><tr><td>28. Solanum multiflorum Roth</td><td>132</td></tr><tr><td>29. Solanum nienkui Merr. & Chun</td><td>137</td></tr><tr><td>30. Solanum peikuoense S.S.Ying in X.Aubriot & S.Knapp, sp. nov.</td><td>140</td></tr><tr><td>31. Solanum poka Dunal</td><td>144</td></tr><tr><td>32. Solanum praetermissum Kerr ex Barnett</td><td>148</td></tr><tr><td>33. Solanum procumbens Lour.</td><td>152</td></tr><tr><td>34. Solanum pseudosaponaceum Blume</td><td>155</td></tr><tr><td>35. Solanum pubescens Willd.</td><td>159</td></tr><tr><td>36. Solanum putii Kerr ex Barnett</td><td>163</td></tr><tr><td>37. Solanum retrorsum Elmer</td><td>166</td></tr><tr><td>38. Solanum robinsonii Bonati</td><td>170</td></tr><tr><td>39. Solanum robustum H.L.Wendl. *</td><td>173</td></tr><tr><td>40. Solanum schefferi F.Muell.</td><td>174</td></tr><tr><td>41. Solanum sisymbriifolium Lam. *</td><td>178</td></tr><tr><td>42. Solanum sulawesi X.Aubriot & S.Knapp, sp. nov.</td><td>179</td></tr><tr><td>43. Solanum torvoideum Merr. & L.M.Perry</td><td>183</td></tr><tr><td>44. Solanum torvum Sw. *</td><td>186</td></tr><tr><td>45. Solanum trilobatum L.</td><td>189</td></tr><tr><td>46. Solanum vagum Nees</td><td>193</td></tr><tr><td>47. Solanum viarum Dunal *</td><td>196</td></tr><tr><td>48. Solanum violaceum Ortega</td><td>197</td></tr><tr><td>49. Solanum virginianum L.</td><td>204</td></tr><tr><td>50. Solanum wightii Nees</td><td>209</td></tr><tr><td>51. Solanum wrightii Benth. *</td><td>213</td></tr><tr><td>Doubtful and suppressed names</td><td>214</td></tr><tr><td>“Names” (designations) not validly published</td><td>215</td></tr><tr><td>Acknowledgements</td><td>218</td></tr><tr><td>References</td><td>219</td></tr><tr><td>Index to numbered collections</td><td>236</td></tr><tr><td>Supplementary materials</td><td>270</td></tr></table>

## Introduction

Solanum L. is one of the ten most species-rich genera of flowering plants (Frodin 2004) and has approximately 1,300 species occurring on all temperate and tropical continents. Species of Solanum have flowers with fused sepals and petals that are usually 5-merous, stellate to pentagonal corollas, stamens with short filaments, and anthers opening by terminal pores. The highest diversity of both groups and species is in tropical South America, concentrated in a circle around the Amazon Basin (see Knapp 2002a), but significant diversity occurs in Africa, Asia, Australia (incl. New Guinea), and the Pacific (Bean 2004, 2016; McClelland 2012; Knapp and Vorontsova
2016; Vorontsova and Knapp 2016; Echeverría-Londoño et al. 2020). *Solanum* was one of Linnaeus's (1753) larger genera; he included 23 species, most of them from Europe, Africa, or Asia. The last time *Solanum* was monographed in its entirety was in De Candolle's *Prodromus* (Dunal 1852), which included 901 species (with an additional 19 recorded as incompletely known by him at the time). Until the 21st century, the taxonomy of *Solanum* was largely limited to rearrangements of infrageneric taxa, species-level treatments of smaller groups within the genus, and floristic works. The large size of *Solanum* and its poorly understood infrageneric structure has meant that *Solanum* taxonomy has proceeded in a piecemeal fashion until relatively recently and the genus had acquired a reputation of being intractable. A project funded by the United States National Science Foundation's Planetary Biodiversity Inventory (PBI) program begun in 2004 has sought to accelerate species-level taxonomic work across the genus and has resulted in a series of monographic and phylogenetic treatments (e.g., Tepe and Bohs 2011; McClelland 2012; Stern et al. 2013; Knapp 2013a; Clark et al. 2015; Särkinen et al. 2015; Wahlert et al. 2015; Aubriot et al. 2016a; Knapp and Vorontsova 2016; Vorontsova and Knapp 2016; Knapp et al. 2017, 2019a; Särkinen et al. 2018). An electronic monographic treatment of the entire genus is being made available online in the web resource Solanaceae Source (http://www.solanaceae source.org). This treatment of the tropical Asian spiny solanums is part of that collaborative effort.

*Solanum* is divided into 12 major clades, of which the Leptostemonum Clade is the most species-rich monophyletic group, comprising 578 of the 1,244 currently recognised species of the genus (Gagnon et al. 2022). Traditionally recognised as sub-genus *Leptostemonum* Bitter, the Leptostemonum Clade is characterised by possession of tapered anthers, stellate trichomes (see Morphology) and epidermal prickles; it has been recognised as a natural group since the time of Linnaeus (1753). While most of the diversity of the clade is in the Americas, considerable species-richness is found in Australia and in tropical Asia.

Here we treat the species of spiny solanums occurring in tropical Asia (see Table 1) excluding taxa found only in Australia and the island of New Guinea where *Solanum* species richness and diversification rates are high (ca. 60 and 170 species estimated for New Guinea and Australia, respectively including introduced taxa) with new species being described regularly (e.g., McDonnell et al. 2019). These taxa have been treated in previous monographs (Symon 1981, 1985; Bean 2004, 2016) and are largely endemic. Species that occur in both those regions and across the wider tropical Asian region, however, are included here (e.g., *S. dunalianum*, *S. schefferi*, *S. torvoideum*). Nepal and Bhutan are also not treated here; both have small portions of territory that are tropical in nature but share all of their spiny solanum species with India and China (see descriptions). Past and future floristic work (Mill 2001; http://www.floraofnepal.org/ onlineflora) treats these taxa in the context of those countries as a whole. Descriptions and full synonymy are provided for all native species (details for introduced species are provided in other sources and on Solanaceae Source, www.solanaceae source.org), and a key to all species, native and introduced, is provided.
<table><caption>**Table 1.** Distribution and status of the species of spiny solanums in tropical Asia. Single country endemics are in bold-face type. Species inclusion in subclades taken from Stern et al. (2011), Vorontsova et al. (2013), Aubriot et al. (2016a) and Gagnon et al. (2022). Country-level distribution is presented in Table 2.</caption><thead><tr><th>Species</th><th>Status in tropical Asia</th><th>Distribution</th><th>Species group in Whalen (1984)</th><th>Subclade (see above)</th></tr></thead><tbody><tr><td>Solanum aculeatisimum Jacq.</td><td>Introduced</td><td>Weedy worldwide in tropics and subtropics; native to southern South America</td><td>S. mammosum group</td><td>Acanthophora</td></tr><tr><td>Solanum aethiopicum L.</td><td>Introduced; cultivated</td><td>Only known from cultivation; originally from Africa</td><td>S. anguivi group</td><td>Anguivi grade</td></tr><tr><td>Solanum arundo Mattei</td><td>Native; possibly introduced?</td><td>India; East Africa</td><td>S. arundo group</td><td>Dennekense clade</td></tr><tr><td>Solanum barbisetum Nees</td><td>Native</td><td>China, India and adjacent Myanmar</td><td>Not included</td><td>Un-named group with S. praetermissum and S. wightii</td></tr><tr><td><strong>Solanum camranhense</strong><br>Dy Phon & Hul</td><td>Native</td><td><strong>Vietnam</strong></td><td>Not included</td><td><strong>S. camranhense</strong> and relatives</td></tr><tr><td>Solanum capsicoideae All.</td><td>Introduced</td><td>Widespread weed in tropics and subtropics; native to southern South America</td><td>S. mammosum group</td><td>Acanthophora</td></tr><tr><td>Solanum chryotrichum Schltdl.</td><td>Introduced</td><td>Weedy in tropics and subtropics; native to Mexico and Central America</td><td>S. torvum group</td><td>Torva</td></tr><tr><td><strong>Solanum comitis</strong> Dunal</td><td>Native</td><td><strong>Indonesia (Java)</strong></td><td>Not included</td><td>Unknown</td></tr><tr><td>Solanum cordatum Forsk.</td><td>Native</td><td>Western India</td><td>Not included</td><td>sister to Giganteum clade</td></tr><tr><td>Solanum cyanocarphium Blume</td><td>Native</td><td>Indochina and Malay Archipelago to Philippines</td><td>Unusual species</td><td>unplaced</td></tr><tr><td><strong>Solanum deflexicarpum</strong><br>C.Y.Wu & S.C.Huang</td><td>Native</td><td><strong>China (Yunnan)</strong></td><td>Not included</td><td>S. violaceum and relatives</td></tr><tr><td>Solanum dunalianum Gaudich.</td><td>Native</td><td>Indonesia (Sulawesi); also on New Guinea and in the Pacific</td><td>S. dunalianum group</td><td>Sahul-Pacific</td></tr><tr><td>Solanum elaeagnifolium Cav.</td><td>Introduced</td><td>Weedy and invasive; native to the Americas (amphitropical)</td><td>S. ellipticum group</td><td>Elaeagnifolium</td></tr><tr><td>Solanum forskali Dunal</td><td>Native</td><td>Western India</td><td>Not included</td><td>Unknown</td></tr><tr><td>Solanum giganteum Jacq.</td><td>Native</td><td>Tropical and subtropical Africa, peninsular India to Sri Lanka</td><td>S. giganteum group</td><td>Giganteum</td></tr><tr><td><strong>Solanum graciliflorum</strong><br>Dunal</td><td>Native</td><td><strong>Indonesia (except Borneo)</strong></td><td>Unusual species (related to S. anguivi group)</td><td>Sahul-Pacific</td></tr><tr><td><strong>Solanum harmandii</strong><br>Bonati</td><td>Native</td><td><strong>Cambodia</strong></td><td>Not included</td><td>Unknown</td></tr><tr><td><strong>Solanum bovei</strong> Dunal</td><td>Native</td><td><strong>India</strong></td><td>Not included</td><td>S. violaceum and relatives</td></tr><tr><td>Solanum insanum L.</td><td>Native</td><td>Tropical Africa to Indochina and the Philippines</td><td>S. incanum group</td><td>Eggplant</td></tr><tr><td>Solanum involucratum Blume</td><td>Native</td><td>Indochina and Malay Archipelago (incl. Christmas Island)</td><td>Not included</td><td>S. expedunculatum and relatives</td></tr><tr><td>Solanum jamaicense Mill.</td><td>Introduced</td><td>Weedy, scattered introductions; native to Caribbean and Central America</td><td>Unusual species</td><td>Micracantha</td></tr><tr><td><strong>Solanum kachinense</strong><br>X.Aubriot & S.Knapp</td><td>Native</td><td><strong>Myanmar</strong></td><td>Not included</td><td>Unknown</td></tr><tr><td>Solanum lasiocarpum Dunal</td><td>Native</td><td>Widespread; cultivated</td><td>S. quitoense group</td><td>Lasiocarpa</td></tr><tr><td>Solanum macrocarpon L.</td><td>Introduced</td><td>Cultivated; relatively widespread, but rare outside Africa</td><td>S. incanum group</td><td>Anguivi Grade</td></tr><tr><td>Solanum mammosum L.</td><td>Introduced</td><td>Widespread weed, sometimes cultivated; native to southern South America</td><td>S. mammosum group</td><td>Acanthophora</td></tr><tr><td>Solanum melongena L.</td><td>Cultivated (native)</td><td>Widespread in cultivation</td><td>S. incanum group</td><td>Eggplant</td></tr><tr><td>Solanum miyakojimense T.Yamaz. & Takushi</td><td>Native</td><td>Japan (Ryuku Islands), offshore islands of Taiwan, Philippines</td><td>Not included</td><td>Unknown</td></tr><tr><td><strong>Solanum multiflorum</strong><br>Roth</td><td>Native</td><td><strong>India</strong></td><td>Not included</td><td>S. violaceum and relatives</td></tr><tr><td>Solanum nienkui Merr. & Chun</td><td>Native</td><td>China (Hainan Island), Vietnam</td><td>Not included</td><td>S. camranhense and relatives</td></tr><tr><td><strong>Solanum peikuense</strong><br>S.S.Ying</td><td>Native</td><td><strong>Taiwan</strong></td><td>Not included</td><td>Torva</td></tr></tbody></table>
<table><thead><tr><th>Species</th><th>Status in tropical Asia</th><th>Distribution</th><th>Species group in Whalen (1984)</th><th>Subclade (see above)</th></tr></thead><tbody><tr><td><strong>Solanum poka Dunal</strong></td><td>Native</td><td><strong>Indonesia</strong></td><td>Not included</td><td>Torva</td></tr><tr><td><em>Solanum praetermissimum</em><br>Kerr ex Barnett</td><td>Native</td><td>Southern China, Indochina to northeastern India</td><td>Not included</td><td>Un-named group with <em>S. barbisetum</em> and <em>S. wightii</em></td></tr><tr><td><em>Solanum procumbens</em><br>Lour.</td><td>Native</td><td>Southern China, Indochina to Indonesia</td><td>Miscellaneous species related to the broad <em>S. anguivi</em> group (as synonym of <em>S. trilobatum</em>)</td><td><em>S. expedunculatum</em> and relatives</td></tr><tr><td><em>Solaum pseudosaponaceum</em><br>Blume</td><td>Native</td><td>Taiwan, Japan (Ryuku Islands), Philippines, southern China, Indochina to Indonesia [Papua New Guinea]</td><td>Not included</td><td>Torva</td></tr><tr><td><em>Solanum pubescens</em> Willd.</td><td>Native</td><td>India</td><td>Unusual species (related to <em>S. somalense</em> Franch.)</td><td>Giganteum</td></tr><tr><td><strong>Solanum putii</strong> Kerr ex Barnett</td><td>Native</td><td><strong>Thailand</strong></td><td>Not included</td><td><em>S. camranhense</em> and relatives</td></tr><tr><td><em>Solanum retorsum</em> Elmer</td><td>Native</td><td>Indonesia, Philippines</td><td>Not included</td><td>unplaced</td></tr><tr><td><strong>Solanum robinsonii</strong><br>Bonati</td><td>Native</td><td><strong>Vietnam</strong></td><td>Not included</td><td><em>S. camranhense</em> and relatives</td></tr><tr><td><em>Solanum robustum</em><br>H.Wendl.</td><td>Introduced</td><td>Weedy, scattered distribution; native to southern South America</td><td><em>S. erythrotrichum</em> group</td><td>Erythrotrichum</td></tr><tr><td><em>Solanum schefferi</em> F.Muell.</td><td>Native</td><td>Indonesia, Philippines [Papua New Guinea, Solomon Islands]</td><td>Not included</td><td><em>S. athenae</em> and relatives; Sahul-Pacific (but see text)</td></tr><tr><td><em>Solanum sisymbriifolium</em><br>Lam.</td><td>Introduced</td><td>Widespread weed; native to southern South America</td><td>Unusual species</td><td>Sisymbriifolium</td></tr><tr><td><strong>Solanum sulawesi</strong><br>X.Aubriot &amp; S.Knapp</td><td>Native</td><td><strong>Indonesia (Sulawesi)</strong></td><td>Not included</td><td>Unknown</td></tr><tr><td><em>Solanum torviforme</em><br>Merr. &amp; L.M.Perry</td><td>Native</td><td>Indonesia [Papua New Guinea]</td><td>Not included</td><td>Torva</td></tr><tr><td><em>Solanum torvum</em> Sw.</td><td>Introduced</td><td>Widespread weed; native to Caribbean and Central America</td><td><em>S. torvum</em> group</td><td>Torva</td></tr><tr><td><em>Solanum trilobatum</em> L.</td><td>Native</td><td>India, Bangladesh, Sri Lanka, Malaysia and Thailand to Indochina</td><td>Miscellaneous species related to the broad <em>S. anguivi</em> group</td><td><em>S. trilobatum</em> + <em>S. usaramense</em></td></tr><tr><td><em>Solanum vagum</em> Nees</td><td>Native</td><td>India, Sri Lanka</td><td>Not included</td><td>unplaced</td></tr><tr><td><em>Solanum viarum</em> Dunal</td><td>Introduced</td><td>Widespread weed throughout; native to southern South America</td><td><em>S. mammosum</em> group</td><td>Acanthophora</td></tr><tr><td><em>Solanum violaceum</em><br>Ortega</td><td>Native</td><td>Widespread weed throughout, but not south of Indonesia</td><td><em>S. anguivi</em> group (as <em>S. violaceum</em> Jacq.)</td><td><em>S. violaceum</em> and relatives</td></tr><tr><td><em>Solanum virginianum</em> L.</td><td>Native</td><td>Widespread from India and Sri Lanka to China; also Arabian Peninsula and (cultivated?) in northern Africa</td><td><em>S. incanum</em> group</td><td>unplaced</td></tr><tr><td><strong>Solanum wightii</strong> Nees</td><td>Native</td><td><strong>India</strong></td><td>Unusual species (as synonym of <em>S. pubescens</em>)</td><td>Un-named group with <em>S. barbisetum</em> and <em>S. praetermissum</em></td></tr><tr><td><em>Solanum wrightii</em> Benth.</td><td>Introduced</td><td>Cultivated; native to Bolivia</td><td><em>S. crinitum</em> group</td><td>Crinum</td></tr></tbody></table>

## Taxonomic history and phylogeny

Solanums from Asia were among the first tropical species to be described by European botanists. Linnaeus described three of the taxa treated here (Linnaeus 1753, *S. me-longena* and *S. trilobatum*; Linnaeus 1767, *S. insanum*), and another four before the beginning of the 19th century. Some of these (e.g., *S. giganteum*) were described from material cultivated in European botanic gardens, as extensive botanical exploration of the region had not yet begun. João de Loureiro, a Portuguese missionary, compiled the first local flora for tropical Asia (Loureiro 1790), based on his long residence in the
<table><caption>**Table 2.** Country distribution of spiny solanums in tropical Asia as delimited here (excluding the island of New Guinea, see Introduction). Introduced species are shown in brackets, single country endemics in **bold face** type.</caption><thead><tr><th>Country</th><th>Species</th></tr></thead><tbody><tr><td>Bangladesh</td><td>lasiocarpum, melongena, praetermissum, (sisymbriifolium), (torvum), trilobatum, violaceum, virginianum</td></tr><tr><td>Brunei Darussalam</td><td>lasiocarpum, (torvum)</td></tr><tr><td>Cambodia</td><td>(capsicoides), cyanocarphium, <b>harmandii</b>, insanum, involucratum, lasiocarpum, (torvum), trilobatum</td></tr><tr><td>China</td><td>(aculeatissimum), (aethiopicum), barbisetum, (capsicoides), (chrysotrichum), <b>deflexicarpum</b>, insanum, (jamaicense), lasiocarpum, (macrocarpon), (mamosum), melongena, nienkui, praetermissum, procumbens, pseudosaponaceum, (sisymbriifolium), (torvum), (viarum), violaceum, virginianum, (wrightii)</td></tr><tr><td>India</td><td>(aculeatissimum), arundo, barbisetum, (capsicoides), (chrysotrichum), cordatum, (elaegnifolium), giganteum, forskalii, <b>hovei</b>, insanum, melongena, <b>multiflorum</b>, praetermissum, pubescens, (robustum), (sisymbriifolium), (torvum), trilobatum, vagum, (viarum), violaceum, virginianum, <b>wightii</b>, (wrightii)</td></tr><tr><td>Indonesia</td><td>barbisetum, (capsicoides), <b>comitis</b>, cyanocarphium, dunalianum, <b>graciliflorum</b>, insanum, involucratum, (jamaicense), lasiocarpum, melongena, <b>poka</b>, procumbens, pseudosaponaceum, retrorsum, schefferi, <b>sulawesi</b>, torvoideum, (torvum), trilobatum, violaceum, virginianum, (wrightii)</td></tr><tr><td>Japan</td><td>(capsicoides), melongena, miyakojimense, pseudosaponaceum, (torvum), trilobatum</td></tr><tr><td>Laos</td><td>(aculeatissimum), barbisetum, (capsicoides), insanum, involucratum, lasiocarpum, praetermissum, procumbens, pseudosaponaceum, (torvum), violaceum</td></tr><tr><td>Malaysia</td><td>(capsicoides), (chrysotrichum), cyanocarphium, insanum, involucratum, lasiocarpum, melongena, procumbens, torvoideum, (torvum), violaceum, virginianum, (wrightii)</td></tr><tr><td>Mauritius and Réunion</td><td>insanum, melongena, (robustum), (torvum), violaceum</td></tr><tr><td>Myanmar (Burma)</td><td>(aculeatissimum), barbisetum, (capsicoides), insanum, <b>kachinense</b>, lasiocarpum, (mamosum), melongena, praetermissum, (torvum), (viarum), violaceum, virginianum, (wrightii)</td></tr><tr><td>Philippines</td><td>cyanocarphium, insanum, (jamaicense), lasiocarpum, (mamosum), melongena, miyakojimense, pseudosaponaceum, retrorsum, schefferi, torvoideum, (torvum), trilobatum, violaceum, (wrightii)</td></tr><tr><td>Singapore</td><td>insanum, lasiocarpum, (macrocarpon), melongena, (torvum)</td></tr><tr><td>Sri Lanka</td><td>(capsicoides), (chrysotrichum), giganteum, insanum, lasiocarpum, (macrocarpon), melongena, (torvum), trilobatum, vagum, violaceum, virginianum</td></tr><tr><td>Taiwan</td><td>(capsicoides), insanum, lasiocarpum, melongena, miyakojimense, <b>peikuoense</b>, pseudosaponaceum, (sisymbriifolium), (torvum), violaceum</td></tr><tr><td>Thailand</td><td>barbisetum, (capsicoides), cyanocarphium, insanum, involucratum, lasiocarpum, (mamosum), melongena, praetermissum, procumbens, <b>puti</b>, (torvum), trilobatum, violaceum, (wrightii)</td></tr><tr><td>Timor-Leste</td><td>insanum, lasiocarpum, procumbens, torvoideum, violaceum</td></tr><tr><td>Vietnam</td><td>(aculeatissimum), <b>camranhense</b>, (capsicoides), cyanocarphium, insanum, involucratum, lasiocarpum, nienkui, praetermissum, procumbens, <b>robinsonii</b>, (torvum), trilobatum, (viarum), violaceum, (wrightii)</td></tr></tbody></table>

southern third of today's Vietnam, then known as 'Cochinchina' (Merrill 1935). He used both the Linnaean sexual and binomial systems and included six species of spiny solanums, only one of which, *S. procumbens*, was newly described.

The Scottish surgeon and botanist William Roxburgh lived and worked in northern India in the late 18th century. He was Superintendent of the British East India Company's botanical garden in Calcutta (Kolkata), and began work on a monumental flora of India, but this was only published posthumously, edited by the British botanist William Carey with comments and additions by Nathaniel Wallich (Roxburgh 1824), who noted that most of the taxa thought new by Roxburgh had already been described earlier. In his notes, Wallich carefully added both distributional and morphological details for all the *Solanum* species described.

Nathaniel Wallich, Danish prisoner-of-war and later director of the Calcutta Botanic Garden, collected intensively in India and Nepal in the early part of the 19th century. He also amassed herbarium specimens from other collectors in the region (De Candolle and Radcliffe-Smith 1981). In 1828 he came to London due to ill health, and spent several years working with many British and continental botanists on the
"Wallich Catalogue" (A numerical list of dried specimens of plants in the East India Company's Museum, collected under the superintendence of Dr. Wallich of the Company's Botanic Garden at Calcutta); this remained an unpublished list of plants from the region (now fully searchable online, see http://wallich.rbge.info/). A treatment of Solanaceae from this herbarium was published by Christian G. Nees van Esenbeck, the director of the herbarium in Breslau (now Wrocław, Poland). He recognised 14 species of spiny solanums, validating one of Wallich's names (*S. vagum*) and describing as new *S. wightii*; the work also presented comprehensive synonymy for all species (Nees van Esenbeck 1834). Few new taxa were added to the understanding of the solanaceous flora of India in the monumental "Flora of British India" (Clarke 1883).

In Indonesia, then under the control of the Dutch East India Company, C.L. Blume served as director of the botanical gardens in Bogor on the island of Java from 1823 to 1826. He published a flora (Blume 1826) based on his collections and observations in which he included nine species of spiny solanums, the majority of which were described as new taxa (*S. canescens* Blume, *S. cyanocarphium*, *S. involucratum*, *S. pseudosaponaceum*, *S. pseudoundatum* Blume). After he returned to Leiden, where he became the director of the Rijksherbarium, Blume tended to reserve new and interesting collections from southeast Asia for himself and impeded work by others working on the rich flora of the region (Stafleu 1966). This situation changed when Friedrich A.W. Miquel switched his interests from the flora of Brazil to that of southeast Asia. Miquel was offered the opportunity to study the collections of Franz Wilhelm Junghuhn, who refused to surrender the specimens collected during his time as a medical officer in Java to Blume and the Rijksherbarium, where he thought they would remain unavailable for others to study (Stafleu 1966). Eventually the directorship of the Rijksherbarium was passed to Miquel, who in the 1850s began his own flora of the region (Miquel 1857), incorporating material from a wide variety of sources. He recognised 28 species of spiny solanums for the region, including some he had not seen material of but expected to find there (e.g., *S. virginianum*, as *S. xanthocarpum* Schrad. & J.C.Wendl.). Two of these were Australian species (*S. horridum* Dunal, *S. brownii* Dunal [as *S. violaceum* R.Br.]) that he suggested might occur on the island of Timor; we have seen no evidence of these taxa there.

Michel-Félix Dunal used all these floristic works in his treatment of Solanaceae for the *Prodromus* (Dunal 1852), but often did not see the material used by earlier authors, so names for spiny solanums in the region proliferated. Of the 53 names that were validly published by Dunal for native tropical Asian spiny solanums in his different taxonomic treatments (Dunal 1813, 1814, 1852), only six are accepted here (*S. comitis*, *S. forskalii*, *S. graciliflorum*, *S. hovei*, *S. lasiocarpum* and *S. poka*). Since the major global monograph of *Solanum* done by Dunal (1852) the taxa from this region have never been treated in other than checklists or regional floras (e.g., Matthew 1983; Singh 1991; Mohanan and Henry 1994; Zhang et al. 1994; Naithani et al. 1997; Hul and Dy Phon 2014).

The early floristic works in general did not discuss relationships of the species they described, but they did always divide the solanums into those with and without spines (more correctly prickles, see Morphology). Dunal (1813, 1816) divided *Solanum* into two major groups, *Inermia* (unarmed solanums) and *Aculeata* (armed solanums), based on presence or absence of prickles. He renamed these groups as section *Pachystemonum*
Dunal, for taxa with stout anthers and no prickles, and grad. ambig. *Leptostemonum* for taxa with tapering anthers that were never glabrous and usually possessed prickles (Dunal 1852). Bitter (1919) recognised and validated *Leptostemonum* at the subgeneric rank, and the group has been demonstrated to be well-supported as monophyletic using phylogenetic reconstruction with DNA sequence data (Bohs 2005; Levin et al. 2006; Weese and Bohs 2007; Stern et al. 2011; Särkinen et al. 2013; Gagnon et al. 2022), if prickly species such as *S. nemorense* Dunal and *S. wendlandii* Hook., now members of the *S. nemorense* group and the *S. wendlandii* group respectively, are excluded (see Stern et al. 2011; Clark et al. 2015; Gagnon et al. 2022).

Schemes for the taxonomic grouping of the many species of the Leptostemonum Clade were presented by Dunal (1852, as grad. ambig. *Leptostemonum* with 19 groups of species), Seithe (1962, 16 sections), Danert (1970, 15 sections), D'Arcy (1972, 22 sections), and Whalen (1984, 33 species groups). Seithe (1962), who used trichome morphology extensively in designing her system, only treated a few of the native species from tropical Asia but did not assign most of them to any one of her sections, instead classifying them as "Stellatipilum" (i.e., spiny solanums). She included *S. barbisetum* and *S. lasiocarpum* (as *S. ferox* L.) as members of her "Simplicipilum" along with members of what is now recognised as the Acanthophora clade (e.g., *S. aculeatissimum*), *S. giganteum* as a member of "Torvaria" (=the Torva clade), *S. pubescens* as the type species of section *Anisantherum* Bitter, *S. nienkui* as a member of section *Graciliflorum* Seithe, and *S. wightii* as a member of section *Nycterium* Dunal. Danert (1967, 1970), focusing on sympodial structure, essentially followed Seithe's (1962) scheme, but did not list component taxa for his sections. D'Arcy (1972) identified or designated lectotypes for all his recognised sections; he, like Danert (1970), did not list component species. He did, however, define section *Lasiocarpa* (Dunal) D'Arcy, which he typified with *S. lasiocarpum*. Whalen's (1984) scheme for Leptostemonum had 33 informally named species groups for which he listed component taxa and one additional "group" of unusual species that he could not place (36 species); this scheme has been the backbone for study of spiny solanums since (Levin et al. 2006; Stern et al. 2011). Whalen (1984) treated the tropical Asian spiny solanums in a variety of groups (see Table 1). Child and Lester (2001) presented a modified sectional classification for *Solanum* based in part on Whalen (1984), but like D'Arcy (1972) did not indicate component taxa for their groups.

Molecular phylogenetic studies identified the spiny solanums from Africa, Asia, and Australia (incl. New Guinea) as a strongly supported monophyletic group (Levin et al. 2006; Stern et al. 2011; Vorontsova et al. 2013), but few tropical Asian species were included in these analyses. Aubriot et al. (2016a) looked at relationships amongst these species of spiny solanums including 60 species from Asia and Australia. They found that the vast majority of African, Asian, and Australian species were part of a large monophyletic grouping, the Eastern Hemisphere spiny clade (referred to as the "Old World clade" in previous publications, e.g., Aubriot et al. 2016a; Echeverría-Londoño et al. 2020), and within it, they recovered a number of well-supported clades often composed of species of intermingled geographical origins. Two clades of South American origin were shown to contain five (for the Torva clade) and two (for the Lasiocarpum clade) species originating from the Asian and Australo-Pacific regions. These disjunctions are likely the
result of long-distance dispersal (Dupin et al. 2016; Echeverría-Londoño et al. 2020). While all the African species were clustered in a number of clades that had been identified previously (see Vorontsova et al. 2013), most of the tropical Asian taxa were part of large polytomies that also included Australian, New-Guinean and Pacific species; only a few Asian species were found to be nested within the largely African clades (*S. deflexicarpum*, *S. hovei*, *S. insanum*, *S. melongena*, *S. multiflorum*, *S. pubescens*, *S. trilobatum*, *S. violaceum* and *S. virginianum*). The phylogenetic backbone was poorly resolved, this has meant we are still unable to clearly define major clades and undertake sound biogeographical and trait evolution analyses for the spiny solanums of tropical Asia. Future study of the evolutionary relationships of the Eastern Hemisphere spiny solanums will depend upon inclusion of many more species from the Pacific, Australia, and New Guinea, where on-going taxonomic work is adding greatly to the species complement (e.g., Bean 2016; McDonnell et al. 2019; Cámara-Leret et al. 2020; McClelland et al. 2020).

# Morphology

## Habit

Spiny solanums in Asia are mostly perennial woody plants (see Fig. 1), but some are short-lived herbaceous perennials, such as the common roadside pioneer *S. violaceum* or the introduced *S. viarum*. Although some species have been characterized as herbs, a truly annual habit is restricted to the cultivated species *S. aethiopicum* and *S. melongena*. Habit varies considerably; species can be erect, prostrate, or climbing, but this distinction is not always clear from herbarium material. Most native species are erect shrubs and usually do not exceed 1–2 m in height. Tree-like shrubs with several stems up to 6 m tall include *S. giganteum* and *S. torvoideum*, but these can reproduce at heights of less than 1 m and reach full height only occasionally. *Solanum wrightii* is cultivated as a shade tree throughout the tropics and subtropics and many other places and can reach 10 cm in diameter when mature. Prostrate or climbing species such as *S. trilobatum* or *S. procumbens* produce long arching stems densely covered in small, curved prickles; these plants rarely rise more than 30 cm above the ground without external support, but they clamber over rocks and other vegetation with the aid of curved prickles. *Solanum schefferi*, however, is a large woody liana with stems to 10 m long. The climbing habit also occurs in American groups and has clearly evolved more than once in the spiny solanums (Whalen 1984; Stern et al. 2011). Some clambering species (e.g., *S. camranhense*, *S. cyanocarphium*, *S. procumbens*, *S. trilobatum*), appear to develop as small shrubs when support is not available.

## Stems

Sympodial growth is characteristic of Solanaceae giving the stems a typical “zig-zag” appearance; details of sympodial structure have proved useful for infrageneric classification within *Solanum* (Child and Lester 1991; Knapp 2002b). Vegetative growth is
<figure><img src="image_2.png" /><figcaption>**Figure 1.** Diversity of habits and habitats for *Solanum* subgenus *Leptostemonum* in tropical Asia *A Solanum giganteum*, a small tree of the tropical forest understory in India and Sri Lanka (field photograph, unvouchered, India) *B S. trilobatum*, a scandent species in its typical habitat, along the road in mangrove area (*Meeboonya et al. RM 245*, Thailand) *C S. lasiocarpum*, an erect shrub found in disturbed and human inhabited areas where it is often cultivated (*Meeboonya et al. RM 272*, Thailand) *D S. cyanocarphium*, a creeper with decumbent stems in forest understory (field photograph, unvouchered, Vietnam) *E S. camranhense*, a scandent shrub endemic to the coastal dunes of South Vietnam (field photograph, unvouchered, Vietnam) *F S. insanum*, the wild progenitor of the brinjal eggplant usually found in degraded areas (*Meeboonya et al. RM 305*, Thailand). Photograph credits: **A** S. More **B, C, F** X. Aubriot; **D** M. Nuraliev **E** S. Hul.</figcaption></figure>
initially monopodial, but with the onset of flowering, becomes sympodial. The inflorescence is developmentally terminal, and stem continuation is initiated in the axil of the leaf below each inflorescence. Each lateral shoot with alternate leaves arranged in a 1/3 phyllotaxic spiral and a terminal inflorescence is termed a sympodial unit. In some cases, when the axes of sympodial units are fused, the inflorescences appear to originate laterally from the middle of an internode; and when growth of the axes is suppressed, the leaves appear paired (geminate) at a node (Danert 1958, 1967).

Characteristics of sympodial structure in Eastern Hemisphere spiny solanums (as defined here) do not define monophyletic groups (Aubriot et al. 2016a), as is the case in other groups (e.g., tomatoes, Peralta et al. 2008). Some species have plurifoliate sympodial units with an indeterminate and variable number of leaves between each inflorescence (e.g., *S. pseudosaponaceum*, *S. schefferi*). Others have difoliate sympodial units with two leaves between each inflorescence. In those taxa with difoliate sympodial units, the leaves are either paired (geminate) and one is often smaller than the other (e.g., *S. comitis*, *S. poka*, *S. torvoideum*) or more often are variably spaced on the axes between inflorescences (e.g., *S. sulawesi*, *S. barbisetum*). Genetic control of the number of leaves per sympodial unit is known to involve the tomato self-pruning (*sp*) locus: the sympodial units of *sp* mutants are terminated early and have fewer leaves (Paran and van der Knaap 2007).

## Leaves

Leaf morphology in the Leptostemonum Clade is very diverse (Fig. 2), not only among groups of species, but also within groups and even within individuals of a single species. The highly plastic size, shape, and lobing of the leaves are often the first characters to be noticed by herbarium taxonomists and attributing undue importance to this variability is one of the causes of excessive synonymy. Once enough specimens have been seen to appreciate the infraspecific variability, however, leaf characters do have great value for species recognition. Leaves of tropical Asian spiny solanums are simple and usually shallowly to deeply lobed. Deeply lobed (i.e., pinnatifid or pinnatisect) leaves (see Peralta et al. 2008) are found only in some individuals of *S. arundo*, *S. multiflorum*, *S. violaceum*, *S. virginianum* and in the introduced *S. sisymbriifolium*.

It is common for members of a single species to display multiple leaf morphologies. Species of dry, open habitats often have very small leaves less than three centimetres in length (e.g., *S. camranhense*, *S. cordatum*, *S. procumbens*, *S. trilobatum*), and others have large, repand leaves to 40 cm long (e.g., *S. involucratum*, *S. lasiocarpum*, the cultivated *S. macrocarpon*). These repand leaves have been interpreted as retention of juvenile leaf morphology at an adult stage (Whalen 1984). Interpretation of leaf morphology in the spiny solanums can be complicated by extreme differences in juvenile and adult leaves (Roe 1966). Juvenile, non-reproductive plants usually have larger, pricklier, more deeply lobed leaves, whereas adult reproductive plants have often smaller, less prickly, and more often entire leaves, especially at distal ends of the shoots (e.g., *S. poka*, *S. torvoideum*, *S. torvum*). Petiole length is also usually longer in leaves of juvenile plants.

Despite the variability in leaf shape within and between species, many taxa can be recognized by characteristic leaf morphology. Leaves that are almost as wide as long are
<figure><img src="image_3.png" /><figcaption>**Figure 2.** Vegetative characters for tropical Asian spiny solanums **A** large and densely hairy repand leaf of *S. lasiocarpum* (Meeboonya et al. RM 287, Thailand) **B** small, pubescent, very shallowly lobed leaf of *S. miyakojimense* (field photograph, unvouchered, Taiwan) **C** entire, pubescent leaf of *S. robinsonii* (Nuraliev 3031, Vietnam) **D** glabrescent and deeply dissected leaf of *S. virginianum* (Sampath Kumar et al. 126968, India) **E** conical straight prickles on a pubescent young stem of *S. hovei* (field photograph, unvouchered, India) **F** strongly hooked prickles on a glabrous young stem and on the abaxial leaf surface of *S. trilobatum* (Meeboonya et al. RM 242, Thailand) **G** needle-like purple prickles on the adaxial leaf surface of *S. cyanocarphium* (field photograph, unvouchered, Vietnam) **H** pubescent young stem of *S. barbisetum* armed with prickles and bristles (Suksathan et al. PS 3832, Thailand). Photograph credits: **A, B, D–F** X. Aubriot **C, G** M. Nuraliev **H** D. Pedersen.</figcaption></figure>
found in *S. camranhense*, *S. cordatum*, *S. trilobatum* and *S. wightii* (Figs 10, 14, 74, 82), moderately to deeply lobed leaves with rounded apices are characteristic of *S. cyanocar-phium* and *S. graciliflorum* (Figs 16, 27), and deeply lobed, pinnatifid or bipinnatifid leaves are found in *S. arundo*, *S. multiflorum*, *S. violaceum*, *S. virginianum*, and in the introduced *S. sisymbriifolium* (Figs 6, 45, 73, 78, 80).

Characteristics of leaf prickles and trichomes are treated under separate sections of this revision.

## Inflorescences

The *Solanum* inflorescence is a scorpioid cyme with flowers in pairs arranged along a simple axis (Whalen 1984; Knapp 2001), with older flowers and fruits at the proximal end and buds developing distally (see Fig. 3). Inflorescences can be unbranched (simple, e.g., *S. barbisetum*), forked (furcate, e.g., *S. peikuoense*) and more or less ‘Y’ shaped with a peduncle of variable length, or more complexly branched and very large (e.g., *S. giganteum*). During inflorescence growth, the inflorescence shoot-meristems develop new axillary branches before terminating in flowers. The study of tomato mutants compound inflorescence (*s*) and *anantha* (*an*) with complex branched inflorescences suggests that transcription factors alter the timing of flower initiation and thus determine the extent of branching and inflorescence size (Lippman et al. 2008).

Most species of tropical Asian spiny solanums have unbranched (e.g., *S. barbisetum*, *S. hovei*, *S. retrorsum*, *S. wightii*) or forked (e.g., *S. peikuoense*, *S. dunalianum*) inflorescences, and many species have both (e.g., *S. arundo*, *S. forskalii*, *S. vagum*). Highly branched complex inflorescences are found in several species (e.g., *S. giganteum*, *S. graciliflorum*, *S. multiflorum*, *S. torvoideum*) but these taxa can sometimes have unbranched inflorescences when young. The number of flowers per inflorescence parallels inflorescence size and varies from 1–150 flowers; this represents the total flower number over the lifetime of an inflorescence and is obtained by counting buds, flowers, fruits, and pedicel scars from any fallen flowers. In general, 1–30 flowers are open at any one time, depending on the size of the inflorescence. The peduncle (distance from the base of the inflorescence axis to the first flower) varies from almost absent (e.g., *S. comitis*, *S. miyakojimense*, *S. torvoideum*) to stout and elongate (e.g., *S. giganteum*, *S. kachin-ense*). In strongly andromonoecious species (e.g., *S. insanum*, *S. macrocarpon*, *S. melon-gena*), the hermaphroditic flower is borne very near the base of the inflorescence and a gap occurs before female-sterile (staminate) flowers arise (see Figs 3E, 22G, H, 33, 42).

## Pubescence

Trichomes are extraordinarily diverse in *Solanum*, including simple, branched, and stellate types with a broad range of morphologies; infrageneric classifications have been proposed on the basis of trichome types (Seithe 1962, 1979). Molecular phylogenetic reconstructions indicate that trichome types do not provide unambiguous definition for monophyletic groups but can be valuable taxonomic characters at the species level (Knapp 2002b; Bohs 2005).
All the species treated in this monograph possess the stellate trichomes characteristic of the Leptostemonum Clade (see Fig. 1 in Vorontsova and Knapp 2016). Minute simple trichomes (papillae) are also present, usually on the new growth; these are sometimes glandular (e.g., *S. torvum*). In the tropical Asian species stellate trichomes are either: 1) porrect, with unicellular acicular rays arranged horizontally in a single plane, and a unicellular midpoint perpendicular to the rays; or 2) multangulate, i.e., with the rays arranged in more than one plane, and sometimes with a midpoint that is longer than the numerous rays; the lepidote trichomes found in some species from Madagascar (e.g., *S. croatii* D'Arcy & Keating in Vorontsova and Knapp 2016) are not present in any of the species treated here, except the introduced *S. elaeagnifolium*. None of the species treated here possesses strictly echinoid trichomes, which are common in the members of the Brevantherum clade (Roe 1971) or in some species of the Dulcamaroid clade (Knapp 2013a). Stellate trichome types can either be stalked (borne on a multiseriate, multicellular base of varying length) or sessile, and eglandular or glandular.

Most species treated here have only porrect-stellate trichomes (e.g., *S. lasiocarpum*, *S. violaceum*). The stalk varies in length and can be up to 0.5 cm long and then the trichomes appear as long bristles with stellae at their apices (e.g., *S. barbisetum*). The midpoint is variable in length (to 2 mm long in *S. barbisetum*) and is sometimes reduced to a rounded structure (e.g., *S. poka*). In some taxa (e.g., *S. cordatum*, *S. schefferi*) the bulbous midpoint can make the trichomes appear somewhat lepidote (with the rays joined together in a plate at the centre). *Solanum comitis* has trichomes in which the midpoint is completely absent, and unusual upwardly pointing rays. Most species have midpoints that are equal in length or slightly shorter than the rays. The introduced *S. torvum* differs from other similar, but unrelated native taxa, like *S. violaceum*, in the simple glandular trichomes found exclusively in the inflorescence. Multangulate trichomes are found in *S. giganteum* and to some extent in *S. arundo* and *S. vagum*; in *S. giganteum* these give the plants a characteristic scurfy, mealy look. They are also found on the upper leaf surfaces of *S. comitis* and stems of *S. cordatum*.

The simple trichomes of the introduced members of the Acanthophora clade (*S. aculeatissimum*, *S. capsicoides*, *S. mammosum*, and *S. viarum*) are usually interpreted as the midpoints of sessile stellate trichomes that lack rays (Nee 1979; Whalen 1984; Levin et al. 2005). A similar situation occurs in section *Gonatotrichum* Bitter of the Brevantherum clade (Stern et al. 2013), where transitions between these trichome types can be seen.

Trichomes are usually translucent, often orange-brown and rusty or white on dried material, and sometimes dark purple on living plants (e.g., *S. barbisetum*, *S. cyanocarphium*, *S. involucratum*, *S. praetermissum*). Young shoots of living plants are sometimes purple-tinged due to the dense purple pubescence; this coloration is often not easily visible in herbarium specimens. Although trichomes of most species retain their structure on drying, those of *S. giganteum* are weak-walled and collapse on drying and are easily brushed off from stems and leaves – they are sometimes characterised as “farinaceous” (e.g., Vorontsova and Knapp 2016); the trichomes of *S. pseudosaponaceum* are also somewhat weak, but not to the extent of those of *S. giganteum*. Trichome density is highly variable and can affect the colour of living plants and dried specimens.
Stellate trichomes are morphologically variable within an individual (even on any given organ), within a species, and among species. Trichomes on the veins of the abaxial leaf surface are often larger and often have more numerous rays than those of the lamina (e.g., *S. violaceum*). Trichomes on the leaf upper surfaces are like those on the abaxial surface but usually smaller and less dense. *Solanum comitis* has unusual multangulate trichomes on adaxial surfaces, with porrect-stellate trichomes abaxially. As is common in *Solanum*, pubescence of new growth is denser than that of mature stems, and usually more glandular.

## Prickles

Prickles in *Solanum* are epidermal in origin and are thought to be modified multicellular stellate trichomes with layers of elongate and lignified cells (Whalen 1984). The common origin of trichomes and prickles can be observed on young stems of *S. barbisetum* where some trichomes develop longer lignified stalks that become prickles with an apical stellate trichome that is later deciduous. Often prickles can themselves bear trichomes, reflecting their epidermal nature. The development of prickles in *Solanum* has not been studied in detail in any species.

In tropical Asian spiny solanums, prickles are diverse and provide useful taxonomic characters (Fig. 2D–H). Prickles can occur on all above-ground parts of a plant except the corolla and the fruit. Density and distribution of prickles vary with the age of the plant and environmental conditions and, thus, are not particularly useful characters; many species can have branches or entire individuals with no prickles. This plasticity has led to much taxonomic confusion (e.g., *S. retrorsum*). A few species have no prickles in most specimens we have seen (e.g., *S. nienkui*, *S. pubescens*, *S. robinsonii*). Where prickles are present, they are variable in length and can be strongly curved (e.g., *S. cordatum*, *S. schefferi*), straight (e.g., *S. hovei*, *S. sulawesi*, *S. torvoideum* and introduced species of the Acanthophora clade such as *S. viarum*), both curved and straight (e.g., *S. pseudosaponaceum*, *S. violaceum*), or extremely long and thin and forming an indument of soft bristles (*S. barbisetum*). Climbing species usually have sharply curved prickles (e.g., *S. cyanocarphium*, *S. procumbens*, *S. schefferi*, *S. trilobatum*). *Solanum arundo* is distinctive in its combination of broad-based curved prickles on stems and long, straight prickles on leaves (Fig. 6).

Colour of prickles is quite variable between and within species or individuals; they can be green, white, greyish or yellowish brown in dried or living material. In some species (e.g., *S. cyanocarphium*, *S. barbisetum*, *S. insanum*, *S. involucratum*, *S. praetermissum*) some or all of the prickles are purple-tinted with the base or the entire structure light to dark purple. Mechanisms leading to different prickle and trichome colour (see above) are not known in *Solanum*.

## Pedicels

Pedicels are usually herbaceous but, at the fruiting stage in large-fruited species, become woody and up to 9 mm in diameter at the base. Pedicels in most species uniformly abscise less than 1 mm from the base or at the base (see Fig. 4). In contrast, in potatoes
<figure><img src="image_4.png" /><figcaption>**Figure 3.** Diversity of inflorescences and flowers in tropical Asian spiny solanums **A** lax, spreading inflorescences and stellate flowers of *Solanum violaceum* (*Sampath Kumar et al. 126945*, India) **B** condensed, recurved inflorescences and stellate flowers of *S. multiflorum* (*Sampath Kumar et al. 126950*, India) **C** inflorescences and large stellate flowers of *S. involucratum* (field photograph, unvouchered, Vietnam) **D** inflorescences and stellate flowers of *S. pubescens* with unequal stamens, one long and recurved (*Sampath Kumar et al. 126956*, India) **E** large rotate flower of *S. insanum* with abundant interpetalar corolla tissues (*Sampath Kumar et al. 126918*, India) **F** many flowered inflorescence and infructescence of *S. pseudosapopaceum* (field photograph, unvouchered, Philippines) **G** many flowered inflorescences of *S. torvum*; flowers with well-developed interpetalar corolla tissues (*Suksathan et al. PS 3815*, Thailand) **H** small stellate flowers of *S. viarum* (*Sampath Kumar et al. 126944*, India). Photograph credits: **A, B, D, E, H** X. Aubriot **C** M. Nuraliev **F** D. Tandang **G** D. Pedersen.</figcaption></figure>
and their relatives, the abscission zone is in the middle of the pedicel (Spooner et al. 2014), and in the Dulcamaroid clade, the pedicel bases are sleeve-like (Bohs 2005; Knapp 2013a). In most species, pedicels are usually straight in bud but recurved in flower and fruit (e.g., *S. poka*, *S. torvoideum*), but in others, they are strongly curved in flower but straighten and become erect during fruit development (e.g., *S. giganteum*). Pedicel curvature in fruit is a useful taxonomic character for distinguishing *S. deflexi-carpum* and *S. multiflorum* from the sympatric *S. violaceum*; the former two taxa have strongly curved pedicels in fruit whereas *S. violaceum* has straight, spreading pedicels (Figs 3A, B, 18, 45, 78). Conspicuously tapered pedicels that are much wider at the distal end are seen in *S. schefferi* (Fig. 67).

## Calyx

Calyx morphology has been useful in *Solanum* taxonomy, mostly due to differences in size and shape of the lobes in flower, but also due to developmental or size differences between the calyx in flower and fruit. In bud, the calyx lobes are fused for some to most of their length, and in fruit the calyx lobes of most species lengthen at least to some degree. In most species of *Solanum*, there is no vasculature between the fused calyx lobes, and corolla expansion can tear the calyx tissue between the lobes, sometimes creating lobes that vary in length (D'Arcy 1986). Shape of the lobe and of its apex can provide useful taxonomic characters. In the species treated here, calyx lobes vary from broadly deltate, deltate to long-triangular, and acuminate. Several species have calyx lobes that arise from a truncate tube that often tears at anthesis (e.g., *S. schefferi*, *S. torvoideum*). The long-styled flowers of the cultivated *S. macrocarpon* and *S. melongena* often have large, foliaceous calyx lobes (Figs 22G, H, 42).

In fruit, the calyx lobes of most species expand to some degree (e.g., Fig. 4C–G). We have reported the length of calyx lobes in fruit relative to mature fruit size where possible in the species descriptions. We have described as accrescent only those calyces that enclose the berry at maturity or for most of its development. In these species, the calyx tube is usually the part that expands and encloses the fruit. *Solanum barbise-tum*, *S. cyanocarphium*, *S. involucratum*, *S. praetermissum* and *S. wightii* have accrescent spiny calyces that almost completely cover the berry (Figs 8, 16, 53, 82); other species have calyx lobes that expand slightly during fruit development but are usually reflexed to expose the fruit (e.g., *S. schefferi*). The introduced *S. sisymbriifolium* has a prickly calyx that encloses the berry during development, but at fruit maturity the calyx lobes split, reflex, and expose the bright red fruit.

## Corolla

The corolla of solanums is sympetalous, usually pentamerous, and actinomorphic. Tetramery occurs in some species (e.g., *S. procumbens*) and has been considered important by earlier workers such as Bitter (1923), but this character varies within species and occasionally within individual plants. We do not consider it to have
taxonomic significance among the species treated here. Species cultivated for fruit (e.g., *S. macrocarpon*, *S. melongena*) often have fasciated flowers and exhibit corolla lobe numbers higher than five; fasciation can be a distinguishing characteristic to tell *S. melongena* from its wild progenitor *S. insanum*. *Solanum pubescens* and *S. vagum* have zygomorphic corollas (see also Androecium below) where the lower two lobes are slightly enlarged relative to the upper three lobes (see Fig. 3D). As in other species of *Solanum*, corolla zygomorphy is correlated with androecial zygomorphy (see below) and has evolved multiple times (Lester et al. 1999; Anderson et al. 2007; Bohs et al. 2007).

Most species treated here have corollas that are white or various shades of purple, but in some species (e.g., *S. graciliflorum*, *S. insanum*, *S. procumbens*, *S. violaceum*) corollas of both colours are found and individuals are either white or purple-flowered (See Figs 3, 78). In many species, the corollas are variously violet-tinged or striped (see Fig. 1 of Vorontsova et al. 2013). Flower colour can be useful in distinguishing similar species, for example, two taxa with zygomorphic androecia differ in flower colour, *S. pubescens* consistently has violet corollas whereas *S. vagum* has white corollas. Corolla colour can sometimes change with flower maturity; in the introduced *S. wrightii*, flowers change from dark violet to white with age (Fig. 73G).

Corolla size varies considerably within the species treated here but can be an important character for differentiating species. For tropical Asian native species, the largest corollas are found in *S. wrightii* and some cultivars of *S. melongena* (to 5 cm in diameter) and the smallest in *S. harmandii*, *S. nienkui* and *S. putii* (to 0.7–1.6 cm in diameter). Most species have corollas in the range of 1–3 cm in diameter.

Corolla shape varies from rotate-stellate to deeply stellate. Rotate-stellate corollas have short lobes relative to the corolla diameter and are lobed less than halfway to the base (e.g., *S. hovei*, *S. insanum*). Stellate corollas are more deeply lobed. We have characterised corollas with long narrow lobes and an extremely short tube (e.g., *S. nienkui*, *S. schefferi*) as deeply stellate. The corolla lobes are more or less spreading (held perpendicular to the pedicel) at anthesis in most of the species treated here, but in some the lobes are strongly reflexed at maturity (e.g., *S. graciliflorum*); this character is difficult to see on herbarium specimens.

Corollas are usually variously stellate-pubescent on their abaxial surfaces; the trichomes are generally smaller and weaker than those of vegetative parts; they also usually lack midpoints. Areas of the abaxial corolla surface exposed in bud generally have denser pubescence composed of more robust trichomes than does interpretalar tissue, which is usually more or less glabrous.

## Androecium

All species of *Solanum* have stamens with relatively small filaments basally fused to the corolla tube and anthers that are always longer than the filaments and dehiscent by apical pores. Members of the Leptostemonum Clade have free, slender, and attenuate anthers with distally directed pores, while the non-spiny solanums usually have
ellipsoid anthers. Tomato anthers bearing an elongate beak are unique in non-spiny solanums and are not anatomically similar to those of spiny solanums (see Peralta et al. 2008). Amongst Asian spiny solanums, anther length broadly parallels corolla size and breeding system (see below) and can be useful for species differentiation. As the flower ages, the terminal anther pores occasionally elongate, and the anthers appear to “unzip” (D’Arcy et al. 1996; Knapp 2002b). Occasional stellate trichomes are found on anthers, especially along the abaxial connective surface.

Some of the species treated here have anthers of slightly different lengths, with two or three longer than the rest (e.g., *S. graciliflorum*, *S. nienkui*, *S. procumbens*). In these taxa the anthers are not markedly different in shape, and only subtly different in size, or occasionally the filaments differ in length. Markedly zygomorphic androecia are found in three species in the region (*S. pubescens*, *S. vagum*, *S. wightii*). *Solanum wightii* has three longer anthers that are markedly curved, especially in hermaphroditic flowers, and two short straighter anthers (see Fig. 82). In *S. pubescens* and *S. vagum* young flowers or buds have the five anthers of more or less equal lengths, but older flowers have one anther significantly longer than the rest (see descriptions, Figs 59, 76). We do not know if this represents a polymorphism in flower type or growth of the anther during anthesis as happens in *S. turneroides* Chodat (see Stern et al. 2013) and some species of *Lycianthes* (Dunal) Hassl. (Dean 2001). Both those cases involve the elongation of the filament, while in *S. pubescens* and *S. vagum*, it seems the anther itself elongates. Insufficient field observations have been recorded to determine if in these species the longest anther deposits pollen on a different part of the bee than do the shorter anthers, as demonstrated in *S. rostratum* Dunal (Bowers 1975; Vallejo-Marín et al. 2010). The differences in stamen length in these two species are not as pronounced as those documented in strongly enantiostylous solanums (e.g., *S. vespertilio* Aiton and *S. lidii* Sunding of the Canary Islands, see Anderson et al. 2007) so any effect on pollen deposition might be quite small, but may be important in facilitating outcrossing as flowers mature.

## Gynoecium

The ovary is spherical to ovoid and usually glabrous over most of its surface, but with some minute glandular hairs; stellate trichomes are usually limited to the apical region near the style junction. The size and pubescence of the ovary were considered taxonomically important characters by Bitter (1923), but we have found few taxonomically significant characters in the gynoecium except ovaries with supernumerary carpels in species cultivated for fruits (e.g., *S. aethiopicum*, *S. macrocarpon*, *S. melongena*). *Solanum involucratum*, *S. lasiocarpum* and *S. sulawesi* have densely pubescent ovaries with the trichomes persisting to the mature fruit stage (Figs 4C, 39, 69). Styles are broadly similar in these spiny solanums and are usually exserted beyond the anthers (except in short-styled flowers in andromonoecious species, see below), often curved, and apically somewhat dilated. *Solanum pubescens* and *S. vagum* have strongly curved styles that are held next to the longest anthers (Figs 3D, 59), but field studies are needed to determine if these species are truly enantiostylous.
<figure><img src="image_5.png" /><figcaption>**Figure 4.** Diversity of fruits and seeds in tropical Asian spiny solanums **A** large oval fruit of *Solanum insanum* (Sampath Kumar et al. 126918, India) **B** condensed infructescence and small rounded fruits of *Solanum hovei* (field photograph, unvouchered, India) **C** large rounded hairy fruit of *S. involucratum* with strongly accrescent and spiny calyx (field photograph, unvouchered, Vietnam) **D** small rounded fruit of *Solanum pubescens* with elongated calyx lobes (Sampath Kumar et al. 126956, India) **E** rounded fruit of *Solanum cyanocarphium* with strongly accrescent and spiny calyx (field photograph, unvouchered, Vietnam) **F** small rounded fruit of *S. trilobatum* in transverse cut (Meeboonya et al. RM 242, Thailand) **G** rounded fruit and accrescent calyx of *S. praetermissum* in transverse cut (field photograph, unvouchered, Vietnam) **H** oval fruit of *Solanum virginianum* in transverse cut (field photograph, unvouchered, India). Photograph credits: **A, B, D, F, H** X. Aubriot **C, E, G** M. Ruraliev.</figcaption></figure>
Styles of many of the species treated here are of different lengths in flowers at differ-
ent positions along the inflorescence rachis. We have called this condition heterostyly
in the species descriptions; it is associated with the derived breeding systems dioecy and
andromonoecy in *Solanum* (Symon 1970; Symon 1979; Whalen and Costich 1986;
Anderson and Symon 1989). We have not seen dioecy in tropical Asian solanums,
but it is common in Australian members of the Leptostemonum Clade (Symon 1970;
Martine et al. 2009, 2019) and occurs in several other *Solanum* clades (Knapp et al.
1998; Anderson et al. 2015). Andromonoecy, on the other hand, is found in several
species of tropical Asian solanums. These species usually have one to few basal flowers
with long styles that function as hermaphrodites and varying numbers of distal flowers
with short styles that function as staminate flowers (e.g., Figs 3E, 4A). Andromonoecy
is described in more detail below (Sex Expression and Breeding Systems).

Fruits

*Solanum* fruits are usually indehiscent 2-carpellate berries with axile placentation and a matrix that can be juicy, gelatinous, or spongy and dry (see Knapp 2002a for review of fruit types in Solanaceae). *Solanum* berries can be variously modified and are occasionally capsule-like and dry (Whalen 1979; Symon 1981; Knapp 2002a; Knapp et al. 2017). Fruits of *Solanum* in tropical Asia are usually not dry at maturity, except for *S. wightii*, whose berries are completely enclosed in the calyx as is found in other solanums with dry, dehiscent berries (e.g., *S. houstonii* Martyn of Mexico, see Knapp et al. 2017). Field observations of the fruits of *S. wightii* throughout their development are a priority.

Most variation in the fruit of tropical Asian *Solanum* species lies in the size, shape,
colour, and thickness or toughness of the pericarp (see Fig. 4). Berry diameters range
from 0.6 to 4.5 cm and individual berries contain few (ca. 7) to many (>200) seeds.
Berries in species with all hermaphroditic flowers (e.g., *S. multiflorum*, *S. violaceum*)
are usually uniformly green when young and ripen to become yellow, then orange,
then bright red and soft with a juicy matrix and thin, shiny pericarp (Fig. 4B, F).
Larger fruits in andromonoecious species are usually striped or marbled white and
green when young and ripen to yellow with thick leathery pericarp (Fig. 4A, H); these
fruits often have a sticky or gelatinous matrix (e.g., *S. insanum*, *S. schefferi*).

Most berries in tropical Asia solanums are spherical or more or less globose. The
cultivated eggplant (aubergine) *S. melongena* has some cultivars in which berries are
not spherical (Fig. 42), some plants of the introduced *S. mammosum* have teat-shaped
berries with basal protuberances (Fig. 41B), and *S. schefferi* has ellipsoid fruit (fide
Symon 1985). Fruit shape is probably controlled by the same genes identified in to-
matoes and peppers; as in the tomatoes, in African spiny solanums, shape features are
more pronounced in larger fruit (Van der Knaap and Tanksley 2003). The elongated
apically pointed fruits of the tomato mutants *ovate* and *sun* resemble fruits of *S. schef-
feri*. Increases in locule number above two are generally found only in species cultivated
for their fruits like *S. melongena*.
## Seeds

Seeds of all spiny solanums treated here are flattened-reniform, somewhat uneven in outline, and have a fine reticulate pattern of testal cell outlines on the seed surface (Lester and Durrands 1984). With a 10× lens, margins of the cells can be seen to be either pentagonal to rectangular (e.g., *S. barbisetum*) or sinuate (e.g., *S. pseudosaponaceum*). This difference in outline of testal cells can be useful in recognising species but can be difficult to see if seeds are not mature. Seed number varies from fewer than ten per berry to more than 200; seed number and fruit size are generally correlated. Most species have seeds in the range of 2–3 mm long, but the seeds of *S. vagum* are the largest at ca. 5 mm long. Seeds of the species treated here are pale yellow to dark orange-brown on herbarium specimens, and pale yellowish tan or creamy white in live plants, but *S. cordatum* and *S. forskalii* of western India have seeds that are dark brown to nearly black.

## Chromosomes

Chromosome numbers for tropical Asian species are, like all of Solanum, based on a base chromosome number of x = 12. Only ten of the native taxa treated here (*S. forskalii*, *S. insanum*, *S. lasiocarpum*, *S. melongena*, *S. multiflorum*, *S. torvoideum*, *S. trilobatum*, *S. vagum*, *S. violaceum* and *S. virginianum*) have published chromosome counts; these are all either n = 12 (haploid counts) or 2n = 24 (diploid counts). None of the species treated here, native or introduced, has been documented as polyploid (expect *S. elaeagnifolium* in South America; see Scaldaferro et al. 2012), but chromosome counts for many species are not yet available.

# Ecology and natural history

## Habitats

Like many species of spiny *Solanum*, tropical Asian taxa are primarily plants of open habitats such as forest clearings, roadsides and areas disturbed by human activities (Fig. 1). The introduced species are usually found in disturbed habitats, and some (e.g., *S. torvum*, *S. viarum*) have become major components of the weedy flora of many areas. Native species occupy a wide range of forest types, from lowland tropical rainforest (e.g., *S. poka*, *S. pseudosaponaceum*) to seasonally dry forests (e.g., *S. nienkui*) to higher elevation grasslands (e.g., *S. hovei*, *S. multiflorum*) and coastal dune systems (e.g., *S. camranhense*). *Solanum arundo*, *S. cordatum* and *S. forskalii* from western India are plants of deserts and extremely dry areas.

In some areas, the adventive species from the Americas like *S. torvum* or *S. chrysotrichum* have achieved local dominance and are completely naturalised. We do not know if they are posing a threat to the less common native taxa, but *S. torvum*, for example,
is certainly the most-collected species from tropical Asia in more recent collections, perhaps indicating not only its commonness but the propensity for collection along roadsides and other disturbed areas.

## Sex expression and breeding systems

Many members of the Leptostemonum Clade exhibit andromonoecy where the first (proximal) “long-styled” flower(s) have styles that protrude beyond the anthers and go on to develop fruits, and the later (distal) “short-styled” flowers have partly developed styles and do not normally develop fruits (e.g., *S. insanum*). Andromonoecy has been extensively studied in *Solanum* (e.g., Dulberger et al. 1951; Whalen and Costich 1986; Anderson and Symon 1989; Miller and Diggle 2003) and is believed to be an adaptation to limited resources which allows the plant to restrict the number of costly fruits without decreasing pollen production. In the spiny solanums there is a continuum from weakly andromonoecious species with a low proportion of staminate flowers (i.e., many hermaphroditic flowers) to strongly andromonoecious species with a high proportion of staminate flowers and only one hermaphroditic flower that sets fruit. A statistically significant correlation has been found between the strength of andromonoecy, larger fruit size, larger ovary size, and larger size of long-styled flowers (Miller and Diggle 2003). Andromonoecy and its correlation with fruit size has formed the basis of many traditional taxonomic systems for spiny *Solanum* (e.g., Bitter 1923 in his treatment of African spiny solanums) but may instead represent a suite of correlated characters driven by breeding system and not by evolutionary relationships. Our phylogenetic studies indicate andromonoecy does not define monophyletic groups (Vorontsova et al. 2013; Aubriot et al. 2016a). Most species of tropical Asian solanums that exhibit heterostyly are only weakly andromonoecious, with several long-styled flowers in the proximal part of the inflorescence. *Solanum lasiocarpum* usually bears one to a few fruits at the base of each inflorescence; *S. melongena* and its wild progenitor *S. insanum* are strongly andromonoecious with usually only a single basal long-styled hermaphroditic flower (e.g., Figs 3E, 33, 42) as is the case also in the introduced *S. macrocarpon* (Fig. 22G, H).

## Uses

Native tropical Asian species of spiny solanums include two significant fruit crops, *S. melongena* and *S. lasiocarpum*. In addition to these, *S. aethiopicum*, the scarlet eggplant native to Africa is cultivated in some areas for its fruits and leaves (for details of this and the following species and their uses see Vorontsova and Knapp 2016). A few collections of the African Gboma eggplant *S. macrocarpon* have been recorded from Singapore and Sri Lanka, these are all over 50 years old and the species does not appear to have been adopted more widely, although Burkill (1935) suggested it was spreading in the early twentieth century. Several other species of spiny solanums are used locally, both as foods and medicines.
*Solanum melongena*, the brinjal eggplant or aubergine, is the second most commercially important fruit crop in the Solanaceae after tomato (*S. lycopersicum* L.; Daunay and Hazra 2012). The English common name refers to early varieties that were imported from Asia with small, white berries; these are still in cultivation and use in Asia but are no longer commonly found in Europe. *Solanum melongena* has been derived from its wild progenitor *S. insanum* (see Knapp et al. 2013) via artificial selection for domestication, possibly in several different areas across the region (Meyer et al. 2012, 2014; but see Page et al. 2019 for an alternative scenario). The taxonomy and phylogenetic relationships of the largely African wild relatives of the eggplant have been extensively worked on in recent years (e.g., Knapp et al. 2013; Vorontsova and Knapp 2016; Aubriot et al. 2018), with clarifications in nomenclature and species circumscription. The crop has a long history of use in tropical Asia (Daunay and Janick 2007; Wang et al. 2008; Chatterjee and van Andel 2019) and many local varieties, both named and un-named, are in current cultivation (e.g., Caguiat and Hautea 2014; Husnudin et al. 2019). Considerable cultivar diversity also exists outside Asia (e.g., Muñoz-Falcón et al. 2009; Hurtado et al. 2012; Cericola et al. 2013), and recent work in adapting agriculture for climate change (e.g., Dempwolf et al. 2014) and for pest resistance has led to considerable interest in the wild relatives of *S. melongena* for crop improvement purposes (e.g., Prohens et al. 2012, 2013; Kaushik et al. 2016; Kouassi et al. 2016; Plazas et al. 2016; Gramazio et al. 2017; Prohens et al. 2017; Taher et al. 2017; García-Fortea et al. 2019). Many of the wild relatives of *S. melongena*, however, are poorly represented in gene banks and threatened with extinction (Syfert et al. 2016).

Eggplants are valued nutritionally for their high phenolic and antioxidant content (e.g., Wu et al. 2013; Gramazio et al. 2014; Kandoliya et al. 2015; see references in Taher et al. 2017) as well as vitamins and other health-beneficial compounds (Naeem and Ugur 2020). Crosses with wild relatives are being explored to increase content of these nutritionally important compounds in cultivated eggplant (e.g., Prohens et al. 2013). Pre-breeding and breeding efforts are actively being pursed in *S. melongena* using modern molecular breeding methods, more details can be found in the chapters of Chapman (2019) and in Gramazio et al. (2019).

The wild progenitor of the cultivated eggplant, *S. insanum* (recently distinguished from the similar *S. incanum* L. of Africa to Pakistan, see Aubriot et al. 2018), is widely used medicinally across tropical Asia (see table 2 in Ranil et al. 2016). It is clearly distinguished from the cultivated *S. melongena* by local people (see Ranil et al. 2016). Among common uses are relief of chest congestion and rheumatism, but in Ayurvedic medicine *S. insanum* (often cited as *S. incanum* or as a variety of *S. melongena*, http://www.instituteofayurveda.org) is used for treatment of a wide variety of ailments, including overall body pain.

*Solanum lasiocarpum* of the mostly American Lasiocarpa clade is widely cultivated for its juicy fruit across the tropics of Asia; fruits are used to make sauces and condiments for curries (Whalen et al. 1981; Heiser 1986). It is not yet a commercially important crop in the region or internationally, most use is from home gardens and local plots (Lim 2012). Various plant parts are also used in medicine for a variety of ailments including toothache, respiratory problems, and venereal disease (Lim 2012); Heiser (1986) reports that *S. lasiocarpum* is used medicinally in China.
Fruits of several other spiny solanum species are also used in cooking; the berries of the introduced *S. torvum* are widely used in curries, and are marketed in Europe as pea eggplants, and we have seen one collection label indicating that the berries of *S. cyanocarphium* are eaten. *Solanum torvum* is widely used as a graft rootstock for eggplant and has been of considerable interest for its biological and pharmacological activity (Jaiswal 2012). Many accounts of *S. torvum* in both the Ayurvedic and Chinese pharmacopeias (Zubaida et al. 2012), mention its use as a vermifuge and for relief from respiratory ailments (as is common for solanums in general). Pharmacolic extracts of *S. torvum* fruit exhibit considerable antibacterial activity and extracts have been shown to include phenolics that are effective in inducing cancer cell death (Zubaida et al. 2012).

The roots of several species of Asian spiny solanum are important components of the Ayurvedic preparation 'Dashamoola' (Daśamūla), also known as the "Ten Roots". This complex preparation includes roots of ten plants, among them *S. violaceum* (as brhatī, usually as *S. indicum* L., but *S. torvum* and *S. insanum* also used) and *S. virginianum* (as kantakarī, Aparna et al. 2012). Daśamūla is used to relieve fevers, oedema, respiratory troubles, rheumatic arthritis, and general debility; it is widely available as an Ayurvedic remedy (https://www.netmeds.com/health-library/post/dashamoola-benefits-uses-ingredients-dosage-and-side-effects).

*Solanum trilobatum* is used in the traditional Siddha medicinal system of southern India (Mohanan et al. 1998) to treat a variety of respiratory ailments, particularly bronchial asthma (Govindan et al. 1999, 2004). Aqueous and alcoholic extracts of whole plants were effective as antimicrobials against a wide variety of microorganisms (Latha and Kannabiran 2006), including *Staphylococcus*. Jain and Borthakur (1986) summarise many uses of *Solanum* in India with reference to previous works; care must be taken, however, with these records as vouchers are not often provided and many of the names used are no longer in use (e.g., *S. ferox*, *S. indicum*, *S. surattense* Burm.f.). Other species of tropical Asian spiny solanums have uses recorded on labels or in local floras (e.g., *S. giganteum*); details for these taxa can be found in individual species descriptions.

## Species concepts

Our goal for this treatment has been to provide circumscriptions for the members of this morphologically variable group of species, while clearly highlighting areas, taxa and populations where further in-depth research would be useful. Delimitation of species here basically follows what is known as the "morphological cluster" species concept (Mallet 1995; Knapp 2008): i.e., "assemblages of individuals with morphological features in common and separate from other such assemblages by correlated morphological discontinuities in a number of features" (Davis and Heywood 1963). Biological (Mayr 1982), phylogenetic (Cracraft 1989) and the host of other finely defined species concepts (see Mallet 1995) are almost impossible to apply in practice and are therefore of little utility in a practical sense (see Knapp 2008). It is important, however,
to clearly state the criteria for the delimitation of species, rather than dogmatically fol-
low particular ideological lines (see Luckow 1995; Davis 1997). Our decisions relied
on clear morphological discontinuities to delimit species. Specific characters used for
recognition are detailed with each species description and in the key. Some poten-
tial reasons for variability and intergradation are recent divergence, hybridisation, and
environmental influence on morphology. In this revision we have tried to emphasise
similarities between populations instead of differences, which so often reflect incom-
plete collecting or local variation. Although infraspecific taxa have been recognised
by others within these taxa, we have not recognised subspecies or varieties, we have
rather described and documented variation where present, rather than formalised such
variability with a name which then encumbers the literature. We have been conserva-
tive in our approach, recognising as distinct entities those population systems (sets of
specimens) that differ in several morphological characteristics. Some of the species in
this area are extremely widespread and variable (e.g., *S. insanum*, *S. pseudosaponaceum*,
*S. torvum*, *S. violaceum*); variation exists in certain characters, but inspection of large
number of specimens reveals no apparent natural breaks in variation but rather a mix-
ing between highly morphologically variable populations. For these widespread species
the pattern of variation is such that no reliable units can be consistently extracted, nor
is geography a completely reliable predictor of character states. Here variability within
and between populations seems more important than the variations of the extremes
other taxonomists have recognised as distinct. We describe this variation realising that
others may wish to interpret it differently.

**Materials and methods**

Our taxonomic treatment is based on study of herbarium specimens and the molecular
phylogenetic study of the spiny solanums of tropical Asia (Aubriot et al. 2016a). De-
limitation and descriptions are based on field work and examination (physical and vir-
tual) of 12,519 herbarium specimens representing 9,211 collections (of which 4,099
collections and 6,149 specimens were from tropical Asia as treated here) from 162 her-
baria: A, AD, AK, ALCB, AMD, ARIZ, AS, B, BA, BAA, BAB, BACP, BH, BHCB,
BISH, BK, BKF, BLAT, BM, BO, BR, BRI, BRLU, BRY, BSD, BSHC, BSI, BSIS,
C, CAL, CAS, CEPEC, CESJ, CICY, COL, CORD, CPUN, CR, CS, CTES, CUZ,
DD, DS, DSM, DUKE, E, EA, ECON, EIU, ENCB, ENLC, ESA, ETH, F, FCQ,
FT, FUEL, FURB, G, G-DC, GH, GOET, GZU, HA, HAL, HAO, HAST, HBG,
HFSL, HIFP, HITBC, HSTM, HUEFS, HUFSJ, IAC, IBK, IBSC, ICN, INB, IND,
INPA, IPA, JBSD, JPB, K, KIEL, KUFS, KUN, K-W, L, LAE, LE, LIL, LINN, LOJA,
LPB, MA, MBK, MBM, MBML, MEL, MERL, MESA, MEXU, MH, MICH, MISS,
MMNS, MO, MOL, MPU, MT, NA, NOU, NSW, NU, NY, OSC, OXF, P, PAL,
PBL, PDA, PE, Q, QAP, QCNE, RB, RENO, RHT, RM, S, SCA, SF, SI, SING, SP,
SPF, SPSF, SZ, TAN, TCF, TI, TNM, U, UBC, UBD, UC, UEC, UNM, UPCB,
UPS, US, USM, UT, UTC, W, WAG, WUK, XAL, YA, Z. Some of these specimens
were examined digitally through individual herbarium portals; we include only those specimens we have been able to unequivocally identify from these images or that are duplicates of collections we have personally examined.

We include detailed descriptions and nomenclature for species native to the region only; introduced taxa are included in the main text with details of distribution and synonyms based on tropical Asian material, in the keys, in Tables 1 and 2 and in the Suppl. materials 1–3. Descriptions for the eleven introduced taxa (S. aculeatissimum, S. aethiopicum, S. capsicoides, S. chrysotrichum, S. elaeagnifolium, S. jamaicense, S. macrocarpon, S. mammosum, S. sisymbriifolium, S. torvum, S. viarum and S. wrightii) are all available on Solanaceae Source (www.solanaceae source.org) and in other monographic works cited in the text (e.g., Vorontsova and Knapp 2016; Knapp et al. 2017), along with complete nomenclatural details for these names and their synonyms; here we have only listed types and nomenclatural details for synonyms based on tropical Asian types.

Measurements were made from dried herbarium material supplemented by measurements and observations from living material. Colours of vegetative organs (e.g., leaves, prickles, trichomes) and seeds are described from dried herbarium collections (and living plants when available), and for corollas, fruits, etc., are described from living material or from herbarium label data. Specimens with latitude and longitude data on the labels were mapped directly. Some species had few or no georeferenced collections; here we retrospectively georeferenced the collections using available locality data. Maps were constructed with the points in the centres of degree squares in a 1° square grid. Conservation threat status was assessed following the IUCN Red List Categories and Criteria (IUCN 2019) using the GIS-based method of Moat (2007) as implemented in the online assessment tools in GeoCat (http://geocat.kew.org). The Extent of Occurrence (EOO) measures the range of the species, and the Area of Occupancy (AOO) represents the number of occupied points within that range based on the default grid size of 2 km². We have used only the EOO in the threat assessments for widespread species; AOO is very sensitive to georeferencing bias and collecting effort.

Where specific herbaria have not been cited in protologues we have followed McNeill (2014) and designated lectotypes rather than assuming holotypes exist. We cite page numbers for all previous lectotypifications. In general, we have lectotypified names with the best preserved, or in some cases with the only, herbarium sheet we have seen; in these cases, we have not outlined our reasoning for the lectotypifications. Where there has been difficulty or where the choice may not be obvious, we detail our reasoning at the end of the species discussions. For names that have been “inadvertently” lectotypified (sensu Prado et al. 2015), we indicated what the original author cited (e.g., “type”, “holotype”) after the lectotype citation.

Type specimens with sheet numbers are cited with the herbarium acronym followed by the sheet number (e.g., SD [acc. # 6543]); barcodes are written as a continuous string in the way they are read by barcode readers (e.g., G00104280, MO-1781232). For those herbaria (e.g., A, GH, NY, US) where the barcode consists of only a number, we cite only the number string. Where herbaria have both barcodes and accession numbers, we always cite the barcode first, followed by the accession number
(e.g., MO-503846, acc. # 3783069); this citation will allow users to access individual sheets where barcode numbers are not human-readable.

Specimens associated with Blume's flora of the East Indies (Blume 1826) are difficult to pin down. We have assumed that the specimens noted as being collected by Blume in L are as noted; and have used these in typifying Blume's names unless better material unambiguously attributable to Blume was available.

When typifying the names coined by Christian Godfrey Nees van Esenbeck in his monograph of East Indian Solanaceae (Nees van Esenbeck 1834) we have used the specimens from his own herbarium, now held in Graz (GZU; Stafleu and Cowan 1981), in preference over those in the East India (Wallich) herbarium at Kew (K). They are annotated by Nees van Esenbeck, and we are sure he saw them; the numbering of individual sheets in the Wallich herbarium can be somewhat chaotic.

Identities of all collections seen for this study are in Suppl. material 1 (Index to Numbered Collections; Suppl. material 1) and full searchable specimen details are available in Suppl. material 2 (tropical Asian specimens only) and Suppl. material 3 (all specimens examined) and in the dataset for this study deposited in the Natural History Museum Data Portal (https://doi.org/10.5519/0rqfzvgd). All paratypes for new taxa described here are cited in the text.

Citation of literature follows BPH-2 (Bridson 2004) with alterations implemented in IPNI (International Plant Names Index, http://www.ipni.org) and Harvard University Index of Botanical Publications (http://kiki.huh.harvard.edu/databases/publication_index.html). Following Knapp (2013a) we have used the square bracket convention for publications in which a species is described by one author in a publication edited or compiled by another, the traditional "in" attributions such as Dunal in DC. for those taxa described by Dunal in Candolle's "Prodromus Systematis Naturalis Regni Vegetabilis". This work is cited here as Prodr. [A.P. de Candolle] and the names are thus attributed only to Dunal. For "ex" attributions we cite only the publishing author, as suggested in the "Code" (Turland et al. 2018). Standard forms of author names are according to IPNI (International Plant Names Index, http://www.ipni.org).

## Taxonomic treatment

*Solanum subgenus Leptostemonum Bitter, the Leptostemonum Clade*
[for synonymy see Whalen 1984]

**Description.** Herbs, vines, scandent or prostrate shrubs, shrubs or small trees; armed or apparently (to almost completely) unarmed; young stems stellate-pubescent, the trichomes multangulate or more often porrect-stellate with the rays all in a single place, occasionally lepidote, sometimes glabrescent; prickles absent, sparse or dense, straight or curved; bark of older stems grey or brown, sometimes glabrescent. Sympodial units plurifoliate or difoliate, the leaves geminate or not. Leaves entire to deeply pinnately lobed, usually stellate-pubescent on both surfaces, sometimes glabrescent
or the trichomes very sparse; pubescence of porrect, multangulate or lepidote stellate trichomes, these sessile or variously stalked, with or without midpoints, the midpoints if present very short and bump-like to elongate. Inflorescences lateral and internodal or opposite the leaves, unbranched to many times branched, usually pedunculate, not bracteate, variously stellate-pubescent; petioles articulated near the base. Flowers actinomorphic or zygomorphic, bisexual (hermaphroditic) or unisexual and the plants andromonoecious; calyx 5-parted (rarely 4-parted or more than 5-parted in cultivated forms of *S. melongena*), usually stellate-pubescent, sometimes glabrescent; corolla 5-parted (rarely 4-parted or more than 5-parted in cultivated forms of *S. melongena*), rotate-stellate to deeply stellate, white, lilac or deep purple, some species polymorphic for flower colour, interpretalar tissue absent to copious; stamens 5 (rarely 4 or more than 5 in cultivated forms of *S. melongena*), the filaments equal or unequal, usually glabrous; anthers equal or unequal, yellow or cream, blunt to strongly tapered, tightly connivent or spreading, dehiscing by terminal pores, the pores usually not lengthening to slits with age; ovary bicarpellate (fasciated in cultivars of *S. melongena*), globose to conical, glabrous or stellate-pubescent; style straight or curved, in andromonoecious species shorter than the anthers and held within the anther cone; stigma minutely to large-capitate or clavate, sometimes bilobed. Fruit a berry, usually globose or nearly globose (but variously shaped in *S. mammosum* and *S. melongena*), the pericarp dry, fleshy or leathery, glabrous or stellate-pubescent, the surfaces shiny or matte; fruiting calyx lobes not enlarging or often accrescent, sometimes completely enclosing the berry. Seeds flattened-reniform, the testal cells sinuate or polygonal in outline. Chromosome number: n = 12, 24, 36 (see Scaldaferro et al. 2012).

**Distribution.** Members of the Leptostemonum Clade are found worldwide, in all habitats but the group is most diverse in the tropics (see Whalen 1984; Bohs 2005; Gagnon et al. 2022). They are often weedy plants of disturbed areas.

**Discussion.** The Leptostemonum Clade is the largest monophyletic group in the genus *Solanum*. The clade is characterised by the possession of stellate trichomes (sometimes modified), prickles (sometimes absent) and long-attenuate, tapering anthers with distally directed pores that do not elongate to laterally dehiscing slits (as do those of other groups of *Solanum*, see Knapp et al. 2019a). Here we have chosen to treat the species occurring in tropical Asia as a group to fill a significant gap in the understanding of the species level taxonomy of spiny solanums. As for other geographically based groupings in spiny solanums, Asian members of the Leptostemonum Clade do not form a monophyletic assemblage (e.g., Aubriot et al. 2016a; Vorontsova and Knapp 2016); when the species treated have been included in phylogenetic studies, their hypothetical evolutionary relationships are provided in species discussion sections. For further discussion and previous assignments of the taxa treated here to species groups see sections on Taxonomy and Phylogeny above and Table 1.

We have cited types but not reproduced synonymy and complete descriptions of the introduced species here; these can be found in the cited monographic works and on Solanaceae Source. Several of these names are lectotypified here because they were
9
Erect shrubs to trees; sympodial units plurifoliate; berries 1.8–3 cm in diameter .................................................................................... *Solanum arundo*

-
Scandent herbs to shrubs to trees; sympodial units difoliate, the leaves geminate; berries 0.3–1.2 cm in diameter.................................................. 10

10
Leaves 7–11 cm long (rarely smaller); corolla 0.5–1 cm in diameter; berries 0.3–0.5 cm in diameter; seeds 6–9 per berry. Indonesia ....................................................
.................................................................................................................. *Solanum graciliflorum*

-
Leaves 2.5–6.5 cm long; corolla 2–3 cm in diameter; berries 0.7–1.2 cm in diameter; seeds 16–47 per berry. India and Indochina................................................
.................................................................................................................. *Solanum trilobatum*

11
Leaves deeply lobed, densely prickly with bright yellow or straw-colored prickles; flowers fragrant. India to China .................... *Solanum virginianum*

-
Leaves entire or shallowly lobed, if prickly only sparsely so, the prickles various, but not bright yellow or straw-colored.................................................. 12

12
Androecium zygomorphic, with one anther markedly longer than the rest. Southern India and Sri Lanka .................................................... *Solanum vagum*

-
Androecium actinomorphic, all anthers the same length.................................................. 13

13
Stem prickles (if present) downwardly pointing (retrorse); leaves narrowly elliptic to lanceolate. Philippines, Indonesia (?Taiwan, Lanyu Island) ....................
.................................................................................................................. *Solanum retrorsum*

-
Stem prickles (if present) not strongly retrorse; leaves orbicular to elliptic. 14

14
Scandent to erect shrub; leaves orbicular, as long as wide. Western India ....................
.................................................................................................................. *Solanum cordatum*

-
Erect herbs or shrubs; leaves ovate to elliptic, 1.5–3 times longer than wide.... 15

15
Inflorescence unbranched; berries usually large (usually >1 cm in diameter), often flattened and/or ridged. Cultivated plants, perhaps escaped from gardens.................................................................................................................. 16

-
Inflorescence forked to many times branched; berries < 1 cm in diameter (not known in *S. kachinense*) .................................................................................. 17

16
Berries 4–6 cm in diameter; flowers heterostylous and the plants strongly andromonoecious; corolla subrotate with abundant interpretalar tissue....................
.................................................................................................................. *Solanum macrocarpon*

-
Berries 1.5–2.5 cm in diameter; flowers all perfect, only occasionally with a few distal staminate; corolla stellate.................................................... *Solanum aethiopicum*

17
Pubescence of multangulate trichomes, these scurfy and deciduous; inflorescence many times branched and erect. India, Sri Lanka *Solanum giganteum*

-
Pubescence of porrect-stellate trichomes, these merely sparse, not deciduous; inflorescence forked or several times branched, not markedly erect ............ 18

18
Leaves drying black or dark brown; leaf base oblique and appearing more or less truncate; major veins 6–8 pairs; corolla 1.5–1.8 cm in diameter. Myanmar.................................................................................................................. *Solanum kachinense*

-
Leaves drying olive green; leaf base acute to cuneate; major veins 5–6 pairs; corolla 2–2.4 cm in diameter. Taiwan .................................................... *Solanum peikuoense*
<table>
  <tbody>
    <tr>
      <td>19</td>
      <td>Trichomes of upper leaf surfaces multangulate (the rays not in a flat plane).....</td>
      <td>20</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Trichomes of upper leaf surfaces porrect-stellate with the rays in a single flat plane....................................................................................................</td>
      <td>21</td>
    </tr>
    <tr>
      <td>20</td>
      <td>Inflorescences many times branched; trichomes scurfy and deciduous; upper leaf surfaces glabrate in older plants. India, Sri Lanka ....................................................</td>
      <td>Solanum giganteum</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Inflorescences unbranched; trichomes not scurfy and deciduous; upper leaf surfaces densely pubescent. Indonesia (Java) ....................</td>
      <td>Solanum comitis</td>
    </tr>
    <tr>
      <td>21</td>
      <td>Inflorescences forked to many times branched ....................................................</td>
      <td>22</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Inflorescences unbranched (simple)....................................................................</td>
      <td>50</td>
    </tr>
    <tr>
      <td>22</td>
      <td>Stem prickles absent (reproductive growth), the stems unarmed ....................</td>
      <td>23</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Stem prickles present (reproductive growth), the stems weakly to strongly armed ....................................................................................................</td>
      <td>26</td>
    </tr>
    <tr>
      <td>23</td>
      <td>Inflorescences stellate-pubescent and densely glandular pubescent, the glandular hairs unbranched; rest of plant eglandular. Introduced and naturalised, widespread....................................................................................</td>
      <td>Solanum torvum</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Inflorescences variously stellate-pubescent, not glandular (unless rest of plant densely glandular pubescent) ....................................................</td>
      <td>24</td>
    </tr>
    <tr>
      <td>24</td>
      <td>Leaves shiny above; berries 1–1.3 cm in diameter. Taiwan....................................</td>
      <td>Solanum peikuoense</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Leaves not markedly shiny above; berries less than 1 cm in diameter............</td>
      <td>25</td>
    </tr>
    <tr>
      <td>25</td>
      <td>Androecium zygomorphic, with one anther markedly longer than the rest; corolla 2–3 cm in diameter; berries 0.8–1 cm in diameter. Southern India and Sri Lanka ....................................................................................</td>
      <td>Solanum vagum</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Androecium actinomorphic, all anthers the same length; corolla 1–1.4 cm in diameter; berries 0.6–0.8 cm in diameter. Philippines, Indonesia (?Taiwan, Lanyu Island)....................................................................</td>
      <td>Solanum retrorsum</td>
    </tr>
    <tr>
      <td>26</td>
      <td>Stem prickles strongly curved downwards (hooked) ............................................</td>
      <td>27</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Stem prickles straight....................................................................................</td>
      <td>36</td>
    </tr>
    <tr>
      <td>27</td>
      <td>Leaves 1–2 times as long as wide (ovate to elliptic ovate).................................</td>
      <td>28</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Leaves more than 2 times as long as wide (elliptic to narrowly elliptic) .....</td>
      <td>32</td>
    </tr>
    <tr>
      <td>28</td>
      <td>Berries > 2 cm in diameter; prickles of leaves straight, usually >10 mm long. Kathiawar peninsula, Gujarat, India ....................................</td>
      <td>Solanum arundo</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Berries < 2 cm in diameter; prickles of leaves various, never 10 mm long and straight ....................................................................................................</td>
      <td>29</td>
    </tr>
    <tr>
      <td>29</td>
      <td>Erect shrubs; berries orange when mature; fruiting pedicels strongly spreading. Widespread in the region ....................................</td>
      <td>Solanum violaceum</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Scandent shrubs; berries red or red-orange when mature; pedicels erect or pendant, not strongly spreading....................................................</td>
      <td>30</td>
    </tr>
    <tr>
      <td>30</td>
      <td>Corolla 2–3 cm in diameter; anthers 7–9 mm long; plants of forests and forest edges. India and Indochina to Philippines ............</td>
      <td>Solanum trilobatum</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Corolla 0.9–2.4 cm in diameter; anthers 3–7 mm long; plants of dry, desert habitats. Western India ....................................................................</td>
      <td>31</td>
    </tr>
  </tbody>
</table>
<table>
  <tbody>
    <tr>
      <td>42</td>
      <td>Scandent shrubs of deserts; leaf bases cordate to rounded; corolla 1.3-2.4 cm in diameter, divided nearly to the base; seeds dark brown, almost black. Western India</td>
      <td><i>Solanum forskalii</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Erect shrubs of many habitats; leaf bases truncate, often oblique; corolla 1.3-3 cm in diameter, divided half to two-thirds of the way to the base; seeds yellow to orange-brown. Widespread in the region</td>
      <td><i>Solanum violaceum</i></td>
    </tr>
    <tr>
      <td>43</td>
      <td>Leaves entire, the margins not lobed. Indonesia (Sulawesi)</td>
      <td><i>Solanum dunalianum</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Leaves lobed, the margins shallowly to deeply dissected</td>
      <td>44</td>
    </tr>
    <tr>
      <td>44</td>
      <td>Fruiting pedicels curved and strongly deflexed. Western Ghats, India</td>
      <td><i>Solanum multiflorum</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Fruiting pedicels erect or spreading, not curved or deflexed</td>
      <td>45</td>
    </tr>
    <tr>
      <td>45</td>
      <td>Leaves ovate; fruiting pedicels strongly spreading. Widespread in the region.</td>
      <td><i>Solanum violaceum</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Leaves elliptic to narrowly elliptic; fruiting pedicels erect or spreading from weight of fruit</td>
      <td>46</td>
    </tr>
    <tr>
      <td>46</td>
      <td>Inflorescence densely and minutely glandular-pubescent, the glandular trichomes simple. Naturalised, widespread throughout, except western India</td>
      <td><i>Solanum torvum</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Inflorescence variously pubescent, no inflorescence trichomes glandular</td>
      <td>47</td>
    </tr>
    <tr>
      <td>47</td>
      <td>Corolla 2-5 cm in diameter; leaf pubescence golden or reddish gold</td>
      <td>48</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Corolla 1-2 cm in diameter; leaf pubescence not markedly rusty-golden, usually tan</td>
      <td>49</td>
    </tr>
    <tr>
      <td>48</td>
      <td>Corolla 2-2.6 cm in diameter; style 6-9 mm long, mature berries yellow to orange yellow; leaf pubescence rusty-golden colour. Indonesia, Philippines</td>
      <td><i>Solanum torvoideum</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Corolla to 5 cm in diameter; style 10-13.5 mm long; mature berries greenish yellow; leaf pubescence reddish brown. Introduced, China, India, Malaysia, Sri Lanka</td>
      <td><i>Solanum chrysotrichum</i></td>
    </tr>
    <tr>
      <td>49</td>
      <td>Calyx lobes strongly keeled; corolla white; berries 0.8-1.5 cm in diameter. Indonesia (except Borneo)</td>
      <td><i>Solanum poka</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Calyx lobes not keeled; corolla purple; berries 0.7-1 cm in diameter. China and Indochina, to Philippines and Taiwan</td>
      <td><i>Solanum pseudosaponaceum</i></td>
    </tr>
    <tr>
      <td>50</td>
      <td>Leaves entire (occasionally the margins somewhat sinuate, but never distinctly lobed)</td>
      <td>51</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Leaves variously lobed</td>
      <td>60</td>
    </tr>
    <tr>
      <td>51</td>
      <td>Stem prickles strongly curved</td>
      <td>52</td>
    </tr>
    <tr>
      <td>-</td>
      <td>Stem prickles straight or absent</td>
      <td>53</td>
    </tr>
    <tr>
      <td>52</td>
      <td>Corolla 2-3 cm in diameter; berries to 5 cm long, ovoid; climbing vines of rainforests. Indonesia, Philippines</td>
      <td><i>Solanum schefferi</i></td>
    </tr>
    <tr>
      <td>-</td>
      <td>Corolla 0.9-1.6 cm in diameter; berries to 0.8 cm long, globose; scandent shrubs of dry habitats. Western India</td>
      <td><i>Solanum cordatum</i></td>
    </tr>
  </tbody>
</table>
53 Flowers strongly zygomorphic, with one or two anthers much longer than the rest and strongly curved..................................................................................54

– Flowers actinomorphic or only weakly zygomorphic, all anthers of equal length or only slightly differing in size, never in shape ....................................56

54 Corolla 3.5–5 cm in diameter; long anthers 2, 12–15 mm long; fruiting pedicels strongly deflexed; berries dry and held inside the accrescent calyx. Western Ghats, India..................................................................Solanum wightii

– Corolla < 3 cm in diameter; long anther 1, < 10 mm long; fruiting pedicels not deflexed; berries soft and fleshy, the fruiting calyx not accrescent........55

55 Flowers white; leaves lanceolate to elliptic, strongly discolorous, eglandular. Southern India and Sri Lanka ..................................................Solanum vagum

– Flowers purple; leaves ovate to broadly triangular, concolorous, densely glandular, sticky to the touch. Eastern India, Sri Lanka ..................................................Solanum pubescens

56 Trichomes of upper leaf surfaces multangulate, all rays pointing upwards; sympodial units difoliate, the leaves geminate; anthers all of equal size. Indonesia (Java)..................................................................................Solanum comitis

– Trichomes of upper leaf surfaces porrect-stellate, the rays in a single plane; sympodial units plurifoliate, the leaves not geminate; anthers often slightly unequal................................................................................................................57

57 Scandent shrubs; flowers often 4-merous. China, Indochina, Indonesia............ ..................................................................................................................Solanum procumbens

– Erect spindly shrubs; flowers 5-merous ................................................................................58

58 Leaf bases attenuate; corolla deeply stellate, divided nearly to the base. Hainan Island, China, southern Vietnam ............................................Solanum nienkui

– Leaf bases cuneate; corolla stellate, divided ca. halfway to the base............59

59 Leaves strongly discolorous, 2–3 times longer than wide; trichomes of stems and leaves with bulbous midpoints. Vietnam ....................Solanum robinsonii

– Leaves only slightly discolorous, less than 2 times longer than wide; trichomes of stems and leaves without bulbous midpoints. Thailand ....................Solanum putii

60 Stem prickles absent or extremely sparse (ca. 1–2 per 10 cm or more of stem)................................................................................................................61

– Stem prickles always present, occasionally very dense................................................64

61 Berries smaller than 1 cm in diameter, several per inflorescence ....................62

– Berries larger than 1 cm in diameter, usually only one or two per inflorescence................................................................................................................63

62 Leaves ovate to suborbicular; corolla 0.8–1 cm in diameter; plants of seashore dunes. Vietnam.................................................................Solanum camranhense

– Leaves elliptic to narrowly elliptic; corolla 1–1.4 cm in diameter; plants of forests. Philippines, Indonesia (?Taiwan, Lanyu Island) ............................................Solanum retrorsum
73 Flowers zygomorphic, with two anthers longer than the rest; berries dry, held inside an accrescent calyx on straight, strongly deflexed pedicels. India ... Solanum wightii

– Flowers actinomorphic; berries fleshy, the fruiting calyx not accrescent; fruiting pedicels not as above ... 74

74 Peduncle absent to 0.15 mm long, the flowers borne at the very base of the inflorescence; fruiting pedicels strongly recurved, woody; ripe berries orange. Ryuku Islands (Japan) to Philippines ... Solanum miyakojimense

– Peduncle to 2 cm long, always present; fruiting pedicels erect or pendant; mature berries red ... 75

75 Corolla 0.8–1 cm in diameter; plants of dunes along seashore. Vietnam ... Solanum camranhense

– Corolla > 1 cm in diameter; habitat not as above ... 76

76 New growth densely stellate-pubescent, the trichomes with 6–10 rays; sympodial units difoliate, the leaves not geminate. Western India ... Solanum forskalii

– New growth sparsely stellate-pubescent, the trichomes with 2–5 rays; sympodial units difoliate, the leaves geminate. Widespread, India to Philippines ...

– New growth sparsely stellate-pubescent, the trichomes with 2–5 rays; sympodial units difoliate, the leaves geminate. Widespread, India to Philippines ... Solanum trilobatum

77 Mature berries densely pubescent, the trichomes with long midpoints; leaves usually large and somewhat repand ... 78

– Mature berries glabrous or with only a few stellate trichomes at the apex; leaves various, not repand ... 80

78 Leaf bases attenuate; leaves widest near the middle; upper leaf surface glabrate and densely prickly. Indonesia (Sulawesi) ... Solanum sulawesi

– Leaf bases truncate; leaves widest in the lower third; upper leaf surfaces pubescent, prickly or not ... 79

79 Berries completely enclosed in an accrescent, prickly calyx; corolla 1–1.2 cm in diameter; anthers 5–6 mm long. Indochina, Malay Archipelago, Christmas Island ... Solanum involucratum

– Berries not enclosed in an accrescent calyx; corolla 2.5–3.5 cm in diameter; anthers 6–8.5 mm long. Cultivated throughout the region ...

– Berries not enclosed in an accrescent calyx; corolla 2.5–3.5 cm in diameter; anthers 6–8.5 mm long. Cultivated throughout the region ... Solanum lasiocarpum

80 Inflorescences with distal staminate flowers and a single to a few basal hermaphroditic flowers, the plants strongly andromonoecious; berries usually > 2 cm in diameter ... 81

– Inflorescences with all flowers hermaphroditic (perfect), if staminate flowers occur these are few and at the very tip of the inflorescence of otherwise hermaphroditic flowers; berries usually < 1 cm in diameter ... 83

81 Prostrate shrubs with densely prickly stems and leaves; leaves glabrescent; flowers fragrant. India to Malay Archipelago ... Solanum virginianum

– Herbs or shrubs, moderately to sparsely prickly; leaves not glabrescent; flowers not fragrant ... 82
82 Inflorescences usually with only a single hermaphroditic flower at the base; staminate flowers 1–2; berries usually large, variously shaped. Cultivated (see description, can be very difficult to distinguish from *S. insanum*). *Solanum melongena*

- Inflorescences with more than one hermaphroditic flower at the base; staminate flowers > 2; berries 1.5–3 cm in diameter, globose. Weedy throughout. *Solanum insanum*

83 Calyx accrescent in fruit, covering more than half of the berry, densely prickly. 84

- Calyx not accrescent in fruit, if enlarged not covering more than half of the berry, moderately to sparsely prickly. 87

84 Leaves deeply divided to pinnatifid; corollas 2–3 cm in diameter; accrescent calyx peeling back at fruit maturity to reveal the red berry. Introduced and adventive, China and India. *Solanum sisymbriifolium*

- Leaves shallowly lobed or entire, not pinnatifid or bipinnatifid; corollas usually less than 2 cm in diameter; accrescent calyx remaining around the berry at maturity. Native plants. 85

85 Scrambling vine or shrub; leaves elliptic to narrowly elliptic; leaf bases attenuate; berries red when mature. Indochina, Indonesia, Malaysia, Philippines. *Solanum cyanocarphium*

- Erect shrubs; leaves broadly elliptic to ovate; leaf bases truncate; berries whitish green when mature. 86

86 Young growth densely prickly and bristly, the bristles long-stalked and some topped with stellate rays; inflorescences 3–10 cm long; corolla 1.8–2.2 cm in diameter. Indonesia, China to Indochina. *Solanum barbisetum*

- Young growth sparsely prickly, not bristly; inflorescences 1.5–3 cm long; corolla 0.7–1.5 cm in diameter. India to China and Indochina. *Solanum praetermissum*

87 Flowers with the anthers slightly unequal, often 4-merous; sympodial units plurifoliate, the leaves not geminate. China, Indochina, Indonesia, Timor. *Solanum procumbens*

- Flowers with anthers of equal size, 5-merous; sympodial units difoliate, the leaves geminate or not. 88

88 Fruiting pedicels strongly reflexed; trichomes of stems and leaves with elongate midpoints to 2 mm long. Western Ghats, southern India. *Solanum multiflorum*

- Fruiting pedicels erect or spreading; trichomes of stems and leaves with midpoints not markedly longer than the rays. 89

89 Calyx lobes long-acuminate, strongly keeled; seeds > 100 per berry. Indonesia (except Borneo). *Solanum poka*

- Calyx lobes deltate, not strongly keeled; seeds 10–20 per berry. 90
90

Leaf bases cuneate to attenuate; upper leaf surfaces moderately to sparsely stellate-pubescent; fruiting pedicels strongly deflexed. Western Ghats, southern India

-

Leaf bases acute or truncate; upper leaf surfaces densely stellate-pubescent; fruiting pedicels spreading. Widespread throughout

## Synoptic character list for tropical Asian spiny solanums

This synoptical character list can be used as a multi-entry key for identification. We have only listed diagnostic characters here, for example, entire and pinnatifid leaves are listed but not lobed leaves in general. For distributional information please see Table 2. The list is intended to be used as a tool via a process of elimination; any character can be selected and in combination with other characters, a smaller selection of species can be obtained, for which the descriptions will be useful for coming to a final identification.

* Plants found in cultivation (agricultural settings or home gardens): aethiopicum, macrocarpon, mammosum, melongena

* Scrambling or prostrate plants: cordatum, cyanocarphium, forskalii, miyakojimense, procumbens, schefferi, trilobatum, wightii

* Plants unarmed (no obvious prickles anywhere on plant): aethiopicum, camranhense, comitis, cordatum, deflexicarpum, dunalianum, giganteum, lasiocarpum, macrocarpon, melongena, miyakojimense, nienkui, peikuoense, pubescens, putii, retrorsum, robinsonii, torvoideum, torvum, vagum, violaceum, wrightii

* Plants drying black on herbarium specimens: giganteum, kachinense, poka, pseudosaponaceum

* Plants andromonoecious (with basal hermaphroditic and distal staminate flowers): arundo, barbisetum, insanum, lasiocarpum, macrocarpon, melongena, schefferi, virginianum, wightii

* Small trees, taller than 3 m: arundo, chrysotrichum, (comitis?), dunalianum, giganteum, peikuoense, pseudosaponaceum, torvoideum, wrightii

* Simple trichomes (never stellate) on stems: aculeatissimum, capsicoides, mammosum, viarum

* Stems white from dense pubescence of multangulate stellate trichomes: arundo, forskalii, giganteum

* Stems with strongly hooked prickles: cordatum, cyanocarphium, graciliflorum, ja maicense, procumbens, schefferi, trilobatum

* Stem prickles straight and strongly retrorse: retrorsum

* Rays of stellate trichomes fused at the base (lepidote or almost lepidote): elaeagnifolium, robinsonii

* Trichomes and/or prickles purple or purplish black in live plants (sometimes also visible on herbarium specimens): barbisetum, cyanocarphium, hovei, involucratum, lasiocarpum, praetermissum (insanum and melongena prickles purple only)
* Leaves on reproductive branches < 1.5 times longer than wide: camranhense, cordatum, forskalii, involucratum, lasiocarpum, miyakojimense, praetermissum, pubescens, sulawesi, trilobatum, virginianum, wightii

* Leaves on reproductive branches entire (without lobes): camranhense, comitis, cordatum, dunalianum, elaeagnifolium, forskalii, giganteum, miyakojimense, nienkui, poka, praetermissum, procumbens, pseudosaponaceum, pubescens, putii, retrorsum, robinsonii, schefferi, torvum, vagum

* Leaves on reproductive branches with secondary lobing (some lobing to pinnate): arundo, multiflorum, sisymbriifolium, violaceum, virginianum

* Leaves glabrous or glabrescent adaxially: aethiopicum, arundo, cordatum, giganteum, graciliflorum, kachinense, macrocarpon, melongena (rarely), peikuoense, retrorsum, trilobatum, vagum, virginianum

* Leaves with bright yellow, straight prickles > 1 cm long: aculeatissimum, arundo, capsicoides, sulawesi, virginianum

* Leaves with only simple trichomes adaxially: aculeatissimum, capsicoides, mammosum, viarum, wrightii

* Pubescence of adaxial leaf surfaces of multangulate trichomes with all rays pointing upwards: comitis

* Pubescence of white mealy multangulate trichomes that are easily rubbed off: giganteum, vagum

* Leaf bases decurrent onto the stem: macrocarpon, robustum

* Leaf bases cordate/truncate: camranhense, cordatum, forskalii, melongena, pubescens, wightii

* Inflorescence many times branched: dunalianum, giganteum, graciliflorum, harmandii, kachinense, multiflorum, peikuoense, pseudosaponaceum, schefferi, torvoideum

* Inflorescence glandular pubescent: aculeatissimum, pubescens, torvum, viarum

* Peduncles absent or very short (< 5 mm): cordatum, miyakojimense, sulawesi, torvoideum, violaceum, wightii

* Calyx lobes foliaceous: macrocarpon, melongena, robustum

* Calyx lobes with a distinct acumen: camranhense, peikuoense, poka, robinsonii, torvoideum, vagum, virginianum

* Corolla stellate-rotate or pentagonal (with abundant interpretalar tissue): comitis, insanum, macrocarpon, melongena, virginianum, wightii

* Corolla deeply stellate (lobed nearly to the base): barbisetum, graciliflorum, kachinense, retrorsum, schefferi, vagum

* Anthers unequal (even slightly so): nienkui, procumbens, pubescens, putii, robinsonii, vagum, wightii

* Anthers with several markedly different in size and shape, strongly curved: pubescens, vagum, wightii

* Calyx strongly accrescent in fruit, more than half covering the berry: barbisetum, cyanocarphium, involucratum, macrocarpon, praetermissum, wightii

* Immature berries marbled green and white: aculeatissimum, arundo, insanum, ja-maicense, miyakojimense, viarum, virginianum
* Mature berry > 3 cm in diameter: aethiopicum, arundo, lasiocarpum, macrocarpon, mammosum, melongena, schefferi, wrightii

* Mature berries not strictly globose: hovei, macrocarpon, mammosum, melongena, miyakojimense, schefferi

* Mature berries red or orange, thin-skinned and fleshy (usually juicy): camranhense, cordatum, deflexicarpum, dunalianum, forskalii, giganteum, hovei, involucratum, jamaicense, lasiocarpum, miyakojimense, multiflorum, nienkui, peikuoense, procumbens, pseudosaponaceum, pubescens, retrorsum, robinsonii, sisymbriifolium, trilobatum, vagum, violaceum

* Mature berries bright yellow when ripe: aculeatissimum, arundo, insanum, violaceum, virginianum

* Mature berries greenish yellow or yellowish green when ripe: chrysotrichum, insanum, melongena, poka, torvoideum, torvum, torvoideum, wightii (just before dehiscence)

* Mature berries white or greenish white when ripe: barbisetum, praetermissum

* Mature berries black or purple when ripe: melongena, peikuoense, torvoideum

* Mature berries leathery: aculeatissimum, arundo, capsicoides, chrysotrichum, elaeagnifolium, insanum, macrocarpon, mammosum, melongena, viarum, virginianum, wrightii

* Mature berry dry, pseudo-capsular or the pericarp shattering: elaeagnifolium, wightii

* Mature berries densely and uniformly pubescent: involucratum, lasiocarpum, robustum, sulawesi

* Inner flesh of berry spongy and not at all juicy: capsicoides, mammosum, melongena

* Seeds > 100 per berry: cyanocarphium, insanum, involucratum, lasiocarpum, poka, pseudosaponaceum, schefferi, sulawesi, torvoideum, virginianum, wrightii

* Seeds 10 or fewer per berry: camranhense, cordatum, forskalii, graciliflorum, hovei, multiflorum, nienkui, procumbens, retrorsum, robinsonii, vagum, violaceum

* Seeds dark brown or blackish brown: cordatum, forskalii

* Seeds with a distinct wing: capsicoides

## Species descriptions

### 1. Solanum aculeatissimum Jacq., Icon. Pl. Rar. 1: 5, t. 41. 1781.

Fig. 5A–C

Only names based on tropical Asian types listed here; for complete synonymy see Nee 1979; Vorontsova and Knapp 2016.

*Solanum khasianum* C.B.Clarke, Fl. Brit. Ind. [J.D. Hooker] 4: 234. 1883. Type. India. Meghalaya [“Assam”]: Khasia Hills, *J. D. Hooker & T. Thomson* [1666] 14 (lectotype, designated by Sen Gupta 1961, pg. 411: CAL; isolectotypes: GH [00077827], K [K000546077], L [L 0003639], W [acc. # 0022656]).

*Solanum cavaleriei* H.Lév. & Vaniot, Bull. Soc. Bot. France 55: 207. 1908. Type. China. Guizhou: “Ly-Po-Hien”, 10 Aug 1899, *J. Cavalerie* 2722 (lectotype, designated here: E [E00284478]).
**Type.** Cultivated in Vienna, Austria, of unknown origin, *Anonymous s.n.* (lectotype, designated by Vorontsova and Knapp 2016, pg. 41: W [acc. # 0022470]).

**Description.** Vorontsova and Knapp (2016: 41–45); http://www.solanaceae-source.org/solanaceae/solanum-aculeatissimum.

**Distribution.** *Solanum aculeatissimum* occurs only sporadically in tropical Asia (see Table 2); it is native to Brazil (Nee 1979) and adventive and widely distributed in Africa, it is less common in tropical Asia than the similar *S. viarum*.

**Common names.** China. ka xi qie (Zhang et al. 1994). Malaysia/Singapore. têrong perat, têrong asam hutan, têrong puyoh, têrong bêlanda, têrong pusat, têrong piat (Burkill 1935), têrong kori, têrong tènang (Sundanese, Burkill 1935). Vietnam. cà ung (Hul and Dy Phon 2014). Common names from Burkill (1935) may also refer to *S. viarum*.

**Discussion.** *Solanum aculeatissimum* is a member of the Acanthophora clade (sensu Stern et al. 2011; Gagnon et al. 2022) as are several other introduced species in tropical Asia (*S. capsicoides*, *S. mammosum*, *S. viarum*) and is most similar to *S. viarum*. It can be distinguished from that species in its long-acuminate (versus deltate) calyx lobes and its minutely stipitate-glandular (versus puberulent) ovary. *Solanum viarum* is more finely and evenly glandular pubescent than is *S. aculeatissimum*.

The herbarium of the French botanist and clergyman Augustin A.H. Léveillé was acquired by the Scottish botanist George Forrest from whence it passed to the Royal Botanic Garden Edinburgh. Vorontsova and Knapp (2016) incorrectly cited a collection in E as the holotype, no herbarium was cited in the protologue. We have selected the specimen at E (E00284478) that corresponds to the description, collector, and locality (Léveillé 1908), as the lectotype for *S. cavaleriei*.

**Specimens examined.** See Suppl. materials 1–3.

## 2. *Solanum aethiopicum* L., Cent. Pl. II 10. 1756.

Fig. 5D, E

No names based on tropical Asian types have been published; for complete synonymy see Vorontsova and Knapp 2016.

**Type.** Ethiopia. Sin. loc., *J. Burser vol. 9 no. 17* (lectotype, designated by Hepper and Jaeger 1985, pg. 391: UPS).

**Description.** Vorontsova and Knapp (2016: 49–56); http://www.solanaceae-source.org/solanaceae/solanum-aethiopicum-0.

**Distribution.** We have recorded *S. aethiopicum* from China and India, it is recorded from Sri Lanka (as *S. integrifolium* Poir.) by Hepper (1987); it is a plant from tropical sub-Saharan Africa (native) but is not known in the wild; widely cultivated in South America, Europe, and Asia.

**Common names.** China. hong qie (Zhang et al. 1994).

**Discussion.** *Solanum aethiopicum* is the scarlet eggplant or gilo. It is sporadically cultivated for its fruits (and possibly leaves) in southwestern China and adjacent India
<figure><img src="image_6.png" /></figure>

A

<figure><img src="image_7.png" /></figure>

B

<figure><img src="image_8.png" /></figure>

C

<figure><img src="image_9.png" /></figure>

D

<figure><img src="image_10.png" /></figure>

E

<figure><img src="image_11.png" /></figure>

F

<figure><img src="image_12.png" /></figure>

G

<figure><img src="image_13.png" /></figure>

H

**Figure 5.** Introduced species of *Solanum*. *Solanum aculeatissimum* Jacq. **A** habit (Bidault *et al*. 3627, Gabon) **B** detail view of a flower (Bidault *et al*. 3627, Gabon) **C** detail view of a fruit (Bidault *et al*. 3627, Gabon). *Solanum aethiopicum* L. **D** detail view of a flower (field photograph, unvouchered, in cultivation at Radboud University, Nijmegen) **E** detail view of fruits (field photograph, unvouchered, in cultivation at the Max Planck Institute for Plant Breeding Research, Cologne). *Solanum capsicoides* All. **F** detail view of a flower (Coronado González 5457, Nicaragua) **G** detail view of a fruit (Coronado González 5457, Nicaragua). *Solanum chrysotrichum* Schltdl. **H** detail of a fertile branch (field photograph, unvouchered, India). Photograph credits: **A–C** E. Bidault **D, E, H** S. Knapp **F, G** I. Coronado González.
for its edible fruits. Cultivars from tropical Asia are usually glabrescent, with large, ribbed and sometimes flattened berries. It can be easily distinguished from the cultivated brinjal eggplant *S. melongena* by its smaller white flowers and red or reddish orange mature berries. It could possibly be confused with the widespread *S. violaceum* (that is somewhat similar to *S. anguivi* Lam., the wild progenitor of *S. aethiopicum*, see Vorontsova and Knapp 2016), but is more glabrescent than that species, the berries are much larger, and the fruiting pedicels are not as strongly spreading.

**Specimens examined.** See Suppl. materials 1–3.

**3. Solanum arundo** Mattei, Boll. Reale Orto Bot. Palermo 7: 188. 1908.
Fig. 6

*Solanum diplacanthum* Dammer, Bot. Jahbr. Syst. 48: 245. 1912. Type. Tanzania. Sin. loc., *Dr. Fischer s.n.* (type: B?, destroyed, no duplicates found).

*Solanum helleri* Standl., Smithsonian Misc. Collect. 68, no. 5: 15. 1917. Type. Kenya. Rift Valley: Northern Frontier: Ewaso Ngiro River, Neumann's Camp, 26 Sep 1911, *E. Heller s.n.* (holotype: US [00027596, acc. # 634351]).

**Type.** SOMALIA. Banaadir: Mogadischo, 30 May 1913, *G. Paoli* 137 (neotype, designated by Vorontsova and Knapp 2016, pg. 74: FT [FT003945]; isotype: FT [FT003946]).

**Description.** Erect shrub to small tree, 2–6 m, densely prickly. Young stems erect, robust, densely stellate-pubescent and densely prickly, with porrect to multangulate, variously stalked trichomes, the stalks to 0.15 mm long, the rays 7–8(–15), 0.05–0.2 mm long, the midpoints reduced or absent, the prickles 5–10 mm long, 2.5–8 mm wide at the base, strongly curved, flattened, pale yellow to orange, densely stellate-pubescent in the lower 1/3; bark of older stems glabrescent to moderately stellate-pubescent, reddish brown. Sympodial units plurifoliate. Leaves simple, lobed, the blades 2–4(–7) cm long, 1.5–2.5(–3.5) cm wide, 1.5–2 times longer than wide, elliptic, concolorous, armed with 2–5 acicular, straight prickles to 12 mm long on both surfaces; adaxial surface glabrescent, with trichomes only at the base or along the midvein; abaxial surface glabrescent to sparsely stellate-pubescent with porrect, sessile or stalked trichomes, the stalks to 0.2 mm long, the rays 7–9, 0.1–0.2 mm long, the midpoints to 0.3 mm long; principal veins 3–5 pairs, further venation not visible or faint; base cuneate to rounded; margins lobed, the lobes 2–4 on each side, 0.2–0.7(–1.5) cm long, deltate to ovate, sometimes with secondary lobing, apically rounded, sometimes obtuse, the sinuses extending 1/4–2/3 of the distance to the midvein; apex broadly acute to rounded; petiole 0.05–0.5 cm long, less than 1/5 of the leaf blade length, densely stellate-pubescent, unarmed or with a few prickles. Inflorescences apparently lateral, 2–3(–4) cm long, unbranched or forked, with 2–8 flowers; 1–3 flowers open at any one time, densely stellate-pubescent, with 0–2 prickles; peduncle 0–4 mm long; pedicels 0.45–1 cm long, erect, articulated at the base, densely stellate-pubescent, unarmed;
<figure><img src="image_14.png" /><figcaption>**Figure 6.** *Solanum arundo* Mattei *A* herbarium specimen collected in India in 1963 (*Safni CNH-2488*)
*B* detail view of flower (*Vorontsova et al. 80*, Kenya) *C* detail view of fruit (*Vorontsova et al. 80*, Kenya).
Photograph credits: *A* © The Director, Botanical Survey of India, Kolkata *B*, *C* M.S. Vorontsova.</figcaption></figure>

pedicel scars spaced 1–4 mm apart. Flowers 5-merous, heterostylous and the plants andromonoecious, with the lowermost 1–2 flowers long-styled and hermaphrodite, the distal flowers short-styled and staminate. Calyx 5.5–9 mm long, the lobes 3–4 mm long, deltate, apically acute to acuminate, sparsely stellate-pubescent, unarmed or with a few prickles. Corolla 2–3.2 cm in diameter, mauve to purple, stellate, lobed for ca. 4/5 of its length, the lobes 7–14 mm long, 3.5–4.5 mm wide, narrowly deltate, spreading, densely stellate-pubescent abaxially, the trichomes porrect, sessile or stalked, the stalks to 0.2 mm, the rays 6–9, 0.2–0.3 mm long, the midpoints reduced or to 0.5 mm long. Stamens equal; filament tube ca. 1.5 mm long; free portion of the filaments 0.5–1.5 mm long; anthers ca. 5.5 mm long, yellow, connivent, tapering, poricidal at the tips, the pores not lengthening to slits with age. Ovary densely stellate-pubescent in the upper 1/3; style 13–17 mm long in long-styled flowers, stout, curved, weakly stel-
late-pubescent in the lower 1/3, ca. 2 mm long in short-styled flowers; stigma clavate, minutely papillate. Fruit a globose berry, 1–2 per infructescence, 1.8–3 cm in diameter, the pericarp smooth, dark green with pale green and cream markings when young, yellow at maturity; fruiting pedicels 0.8–1.5 cm long, 1.5–2 mm in diameter at the base, woody, pendulous, usually unarmed but occasionally with a few prickles; fruiting calyx not markedly accrescent, but elongating to 7–12 mm long, somewhat fleshy and covering ca. 1/4 of the mature fruit (reflexed in herbarium sheets and on old fruits), unarmed or with up to 10 prickles. Seeds ca. 20–40 per berry, 2.2–3.2 mm long, 1.8–2.2 mm wide, flattened-reniform, dull yellow to orangish brown, the surfaces minutely pitted, the testal cells sinuate in outline. Chromosome number: not known.

**Distribution (Fig. 7).** *Solanum arundo* is an African species, found primarily in eastern Africa from Somalia to Tanzania, in tropical Asia it occurs only in far western India on the Kathiawar peninsula in the state of Gujarat.

**Ecology and habitat.** *Solanum arundo* is a plant of grasslands and savannahs in Africa (Vorontsova and Knapp 2016); in India it is found in seaside vegetation (Sen Gupta 1963).

**Common names and uses.** There have been no common names or uses recorded for *S. arundo*, but in Africa it is often used as a hedge plant, due to its ability to form thick impenetrable thickets (Vorontsova and Knapp 2016).

<figure><img src="image_15.png" /><figcaption>**Figure 7.** Distribution of *S. arundo*.</figcaption></figure>
**Preliminary conservation status (IUCN 2019).** Least Concern (LC); EOO (1,277,240 km²), AOO (216 km²). *Solanum arundo* has a broad distribution in Africa, and although it is relatively poorly represented in India, it is not of particular conservation concern based on its worldwide distribution. The distribution and occurrence of *S. arundo* on the Kathiawar peninsula need to be confirmed with modern collections.

**Discussion.** *Solanum arundo* is a distinctive small extremely prickly tree, in Africa it is often associated with human habitation (Vorontsova and Knapp 2016). It is easy to distinguish from other spiny solanums in western India by the combination of thick, curved, and flattened prickles on the densely stellate- or multangulate-pubescent stems, and long, straight prickles on the leaves. *Solanum forskalii* is sympatric with *S. arundo* and has similar white-pubescent stems, but it is a smaller, scandent plant, with truncate to cordate rather than cuneate leaf bases, smaller corollas (1.3–2.4 versus 2–3.2 cm in diameter) and much smaller fruits (0.6–0.9 versus 1.8–3 cm in diameter). In 2018, one of us (SK) erroneously identified the specimens of *S. arundo* in CAL as *S. forskalii* (Fig. 6).

Vorontsova et al. (2013) resolved *S. arundo* as sister to the more narrowly distributed African endemic *S. dennekense* Dammer, a similar treelet with curved stem spines, white stems, and large, leathery berries.

Sen Gupta (1963) suggested that *S. arundo* had arrived in India with Arab traders in the nineteenth century, as part of the extensive Gujarati trade routes established across the Arabian Sea. Its restricted distribution on the Kathiawar peninsula certainly supports this idea. *Solanum arundo* has not been collected, to our knowledge, since the 1960s, re-evaluation of its presence and distribution in western India is necessary.

**Specimens examined.** See Suppl. materials 1–3.

**4. *Solanum barbisetum* Nees, Trans. Linn. Soc. London 17(1): 51 1834.**

Figs 2H, 8

*Solanum eriophorum* Dunal, Prodr. [A. P. de Candolle] 13(1): 249. 1852. Type. Myanmar. Tanintharyi: “Tavoy” [Dawei], 12 Aug 1827, *N. Wallich s.n.* [Wallich Catal. Burm. 1328] (holotype: G-DC [G00145974]).

**Type.** MYANMAR. Tanintharyi Region: “Tavoy” [Dawei], Aug 1827, *N. Gómez 9071* (lectotype, designated by Hul and Dy Phon 2014, pg. 34: K [K000759381]); isolectotypes: GZU [GZU000255503], LE).

**Description.** Herbs to small shrubs to 1 m tall, heavily armed. Stems erect, terete, densely prickly and pubescent, the pubescence deciduous with age leaving only prickles and bristles on older stems; prickles of varying sizes to 0.5 cm long, broad-based, straight, yellowish tan in dry material, purplish black or yellowish tan in live plants, grading into long-stalked bristles and stellate trichomes; pubescence of porrect-stellate trichomes, mixture of sessile, short- and long-stalked, often recorded as purple-tinged or blackish red, the stalks multiseriate, to 3 mm long, the rays 4–6, 0.5–1 mm long, thin and brittle, the midpoints absent on stalked trichomes, the sessile trichomes with
<figure><img src="image_16.png" /><figcaption>**Figure 8.** *Solanum barbisetum* Nees A herbarium specimen collected in Laos in 1932 (*Poilane* 20487, P00055977) B habit and leaves (*Suksathan et al. PS 3832*, Thailand) C detail of the calyx with stellate trichomes and bristles (*Suksathan et al. PS 3832*, Thailand) D many flowered inflorescence (*Suksathan et al. PS 3832*, Thailand) E detail view of a flower (*Suksathan et al. PS 3832*, Thailand). Photograph credits: A CC-BY, Muséum national d'Histoire naturelle, Paris B–E D. Pedersen.</figcaption></figure>

elongate midpoints to 2 mm long, always longer than the rays; new growth densely pubescent with mixture of short- and long-stalked stellate trichomes; bark of older stems greyish brown. Sympodial units difoliate, the leaves not geminate, or occasionally
unifoliate in very small plants. Leaves simple, shallowly lobed, the blades (7–)12–30 cm long, (5–)10–17 cm wide, 1.5–1.7 times longer than wide, broadly elliptic to somewhat ovate, chartaceous, discolorous (paler green beneath fide *Maxwell 91-651*), sparsely armed along the midrib and major veins with prickles to 1 cm long; adaxial surface dark green, sparsely pubescent with sessile porrect-stellate trichomes, the rays 0–4, 0.1–0.5 mm long, the midpoints 2–3 mm long, delicate and thin; abaxial surface with similar sessile porrect-stellate trichomes, but these denser, especially along the veins; major veins 4–7 pairs, densely pubescent especially abaxially, in live plants often purple-tinged; base abruptly truncate, somewhat oblique; margins shallowly lobed, the lobes 4–7 on each side, occasionally somewhat secondarily lobed, to 1 cm long, more or less broadly deltate, apically acute, the sinuses less than halfway to the midrib; apex acute; petioles 3–9 cm long, half as long to almost as long as the leaf blades, prickly and sparsely pubescent, the prickles to 1 cm long, straight, grading into bristles that themselves grade into a few long-stalked stellate trichomes, the pubescence largely of sessile stellate trichomes with 5–6 rays 0.5–1 mm long and midpoints to 2 mm, always longer than the rays. Inflorescences (1–)3–10 cm long, internodal and lateral, unbranched, with 10–40 flowers, few flowers open at any one time, densely bristly and pubescent with trichomes like those of the stems, the bristles sparser distally with early deciduous rays at the apex grading into prickles; peduncle 0.5–2 cm long, unarmed or armed with a few prickles; pedicels 0.5–0.8 cm long, 0.5–0.7 mm in diameter at the base and apex, slender and nodding at anthesis, densely bristly and stellate-pubescent like the inflorescence axes, articulated at the base; pedicel scars irregularly spaced 3–4 mm apart. Buds long-tapering and somewhat fusiform, almost completely enclosed in the foliaceous calyx. Flowers 5-merous, heterostylous and the plants weakly andromonoecious, with most flowers long-styled and only the most distal short-styled, these drop after flowering and the whip-like inflorescence axis tip persists in fruit. Calyx with the tube 2.5–5.5 mm long, deeply cupulate to somewhat urceolate, densely bristly with bristles to 5 mm long, these elongating in fruit, the lobes 5–8 mm long, 3–4 mm wide, lanceolate to broadly triangular, densely stellate-pubescent abaxially with sessile porrect-stellate trichomes with 4–6 weak rays and an elongate midpoint. Corolla 1.8–2.2 cm in diameter, white or violet (usually adaxially white and abaxially violet, but not always), deeply stellate, lobed nearly to the base, interpretalar tissue absent, the lobes 8–10 mm long, 1.5–3 mm wide, narrowly deltate, spreading to recurved at anthesis, glabrous adaxially, densely stellate-pubescent abaxially with sessile trichomes with elongate midpoints, these densest at the tips. Stamens slightly unequal, with 2 slightly longer than the rest; anthers 8.5–10 mm long, 2 slightly longer, ca. 1 mm wide, strongly tapering, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying; filament tube minute, glabrous; free portion of the filaments minute, glabrous, the anthers almost sessile. Ovary conical, glabrous; style (long-styled flowers) 8–10 mm long, glabrous, ca. 3 mm long in short-styled flowers; stigma capitate, the surfaces minutely papillose, bright green in live plants. Fruit a globose berry, 6–12 per infructescence, 1–1.4 cm in diameter, pale greenish white, completely enclosed in the bristly calyx tube, the pericarp thin and more or less shiny, glabrous; fruiting pedicels 0.7–0.9 cm long, ca. 1 mm in diameter at the base,
1.7–2 mm in diameter at the apex, somewhat woody, spreading to pendent; fruiting calyx greatly expanded to enclose the berry, the tube densely bristly and surrounding the berry, the lobes to 1 cm long, 0.3 cm wide, stellate-pubescent. Seeds 20–30 per berry, 2.5–5 mm long, (1.5)2–3 mm wide, flattened reniform, pale tan or yellowish brown (white in live plants), the surfaces minutely pitted, the testal cells pentagonal in shape. Chromosome number: not known.

**Distribution (Fig. 9).** *Solanum barbisetum* occurs from southern China (Yunnan) and northeastern India to Laos and Thailand.

**Ecology and habitat.** *Solanum barbisetum* grows in open areas, in fields and along forest edges in mixed broadleaf forests; usually from 300 to 2,000 m elevation, more rarely at sea level.

**Common names and uses.** China. ci bao qie (Zhang et al. 1994). Thailand. Nak-hon Si Thammarat: ma uk pa (*Rabil Bunnag* 204); North: ma khûa chê pâ [Lao] (*Winit Wanadorn* 1424).

Fruits (ripe berries) said to be eaten in India (Jain and Borthakur 1986).

**Preliminary conservation status (IUCN 2019).** Least Concern (LC); EOO (1,244,077 km²), AOO (248 km²). *Solanum barbisetum* is widely distributed and is a plant of disturbed areas such as field and forest edges; the small AOO certainly reflects collection bias.

<figure><img src="image_17.png" /><figcaption>**Figure 9.** Distribution of *S. barbisetum*.</figcaption></figure>
**Discussion.** *Solanum barbisetum* is a distinctive species with its elongate inflorescences, berries enclosed in an accrescent calyx and copious long-stalked stellate trichomes on all vegetative parts. It is morphologically most similar to *S. praetermissum* and to a lesser extent *S. involucratum*; it shares with both those species berries enclosed in accrescent calyces and large leaves. *Solanum involucratum* is not sympatric with *S. barbisetum* and is a more robust plant with pubescent berries and shorter inflorescences. *Solanum praetermissum* is more or less sympatric with *S. barbisetum* and has been treated as a variety of *S. barbisetum* in the past (Clarke 1883, see description of *S. praetermissum*). *Solanum barbisetum* differs from *S. praetermissum* in its bristlier pubescence, with the calyx trichomes becoming stiff and prickly as the fruit matures and its more attenuate leaf bases. The calyx pubescence of *S. barbisetum* is often purple-tinged; this is even visible in quite old herbarium sheets.

*Solanum barbisetum* was treated under this species name for Bhutan in Mill (2001), but with the note that “Most specimens from our area labelled ‘*S. barbisetum*’ belong, or appear to belong to *S. griffithii*” (Mill 2001: 1059). The correct name for *S. griffithii* (Prain) Wu & Huang is *S. praetermissum* (see description); care should be taken with the identification of material from Bhutan for these taxa.

The phylogenetic affinities of *S. barbisetum* are unclear. In the analyses of Aubriot et al. (2016a) it is resolved as sister to the ‘S. expedunculatum and relatives’ clade (*S. expedunculatum* Symon, *S. heteracanthum* Merr. & L.M.Perry, *S. involucratum* and *S. procumbens*) but this is only supported with Bayesian inference. It might also be closely related to the morphologically similar *S. praetermissum* but that relationship is not clearly supported in molecular analyses (Vorontsova et al. 2013; Aubriot et al. 2016a).

**Specimens examined.** See Suppl. materials 1–3.

**5. *Solanum camranhense* Dy Phon & Hul, Fl. Cambodge, Laos & Vietnam 35: 16. 2014.**

Figs 1E, 10

**Type.** VIETNAM. Khánh Hòa: “Province Nha Trang, dunes littorales de Cam Ranh, My La face à la lagune de Bau Ro”, 7 Mar 1961, *Lê Công Kiệt 94* (holotype: P [P00055921]; isotype: P [P00055922]).

**Description.** Scandent shrubs, to 1.5 m tall, unarmed or sparsely prickly. Stems more or less erect, terete, unarmed or occasionally with a few scattered tiny prickles, sparsely to densely stellate-pubescent; prickles to 1.25 mm long, to 1 mm in diameter at the base, straight or curved, acicular to deltate, orange, glabrous; pubescence of mixed sessile and very short-stalked porrect-stellate trichomes, the stalks to 0.1 mm long, the rays 6–9, 0.1–0.4 mm long, the midpoints absent or up to 0.1 mm long; new growth densely stellate-pubescent, light brownish in dry material; bark of older stems brownish grey, glabrescent. Sympodial units plurifoliate, the leaves not geminate. Leaves simple, not lobed, the blades 2–3.5 cm long, 1.5–2.5 cm wide, ca. 1–1.5 times longer than
<figure><img src="image_18.png" /><figcaption>**Figure 10.** *Solanum camranhense* Dy Phon & Hul **A** herbarium specimen (holotype) collected in Vietnam in 1961 (Lê Công Kiệt 94, P00055921) **B** inflorescence (field photograph, unvouchered, Vietnam) **C** detail view of the fruits (field photograph, unvouchered, Vietnam). Photograph credits: **A** CC-BY, Muséum national d'Histoire naturelle, Paris **B**, **C** S. Hul.</figcaption></figure>

wide, broadly ovate to suborbicular, chartaceous, slightly discolorous, unarmed; adaxial surface densely stellate-pubescent, the stellate trichomes porrect, sessile to stalked, the stalks to 0.1 mm, the rays 6–8, 0.1–0.4 mm long, the midpoints to 0.1 mm; abaxial surface densely stellate-pubescent with trichomes like those of the adaxial surface; major veins 3–5 pairs, drying yellowish light-green; base truncate to subcordate; margins entire or shallowly sinuate; apex obtuse; petioles 0.4–1 cm long, 1/5–1/3 of the leaf blade length, unarmed and densely stellate-pubescent, the pubescence of sessile and short-stalked stellate-trichomes like those of the blades. Inflorescences 1.5–2 cm long, internodal and lateral, sometimes appearing terminal, unbranched, with ca. 4–7 flowers, only 1 or 2 flowers open at any one time, densely stellate-pubescent, with a mix of sessile and short-stalked porrect trichomes like those of the stems, unarmed;
peduncle 0.5–2 cm long, unarmed; pedicels 5–9 mm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, spreading to erect, unarmed, densely stellate-pubescent with porrect trichomes like those of the inflorescence axes, articulated at the base; pedicel scars irregularly spaced 0.5–4 mm apart. Buds elongate ellipsoid, more or less strongly exserted from the calyx before anthesis. Flowers 5-merous, apparently all perfect. Calyx with the tube ca. 3 mm long, campanulate, the lobes 2–3 mm long, ca. 1 mm wide, deltate and constricting to a short acumen, the acumen 1/4–1/3 the total lobe length, unarmed and densely stellate-pubescent abaxially with porrect-stellate trichomes like those of the pedicels. Corolla 0.8–1 cm in diameter, blue to light purple, stellate, lobed ca. 3/4 of the way to the base, the lobes 5–7 mm long, 1.5–2 mm wide, deltate, spreading at anthesis, densely stellate-pubescent abaxially on parts exposed in bud. Stamens equal; anthers 4–6 mm long, ca. 0.75 mm wide, tapering, orange, glabrous, poricidal at the tips, the pores not lengthening to slits with age; filament tube <0.5 mm long, glabrous; free portion of the filaments 0.5–1 mm long, glabrous. Ovary globose, with minute glandular hairs; style 7–8.5 mm long, slender, curved at the apex, glabrous; stigma capitate, minutely papillate. Fruit a globose berry, several per infructescence, 0.5–0.8 cm in diameter, the pericarp thin and smooth, red when mature, glabrous; fruiting pedicels 0.7–1 cm long, 0.5–1 mm in diameter at the base, 1.6–2 mm in diameter at the apex, woody, erect to spreading, straight to slightly deflexed, unarmed; fruiting calyx lobes not expanding, 1/2–2/3 the length of the mature fruit, broadly deltate, reflexed, unarmed. Seeds 8–10 per berry, 2.5–3 mm long, 2–2.5 mm wide, flattened-reniform, dull yellow, the surface minutely pitted, the testal cells pentagonal in outline. Chromosome number: not known.

**Distribution (Fig. 11).** Solanum camranhense is endemic to Vietnam; the few known collections are restricted to Khánh Hòa and Bình Thuận provinces of South Vietnam.

**Ecology and habitat.** Solanum camranhense has only been collected on coastal dunes of stabilized red sands; 15–20 m elevation.

**Common names and uses.** Vietnam. Khánh Hòa: cù vè [Vietnamese] (Chevalier 38932).

**Preliminary conservation status (IUCN 2019).** Endangered (EN [B2ab(i,ii,iii)]); EOO (555 km²), AOO 16 km²). Due to the paucity of collections, it is difficult to document the range of Solanum camranhense with confidence. However, its occurrence in the fragmented and anthropogenically disturbed habitats of coastal southern Vietnam (Wikramanayake et al. 2002) suggests it is of conservation concern.

**Discussion.** Solanum camranhense is morphologically similar to the sympatric *S. robinsonii*, but differs from that species in its scandent (versus erect) habit, the denser pubescence that dries yellowish brown, shorter leaves (2–3.5 cm long versus 3–8 cm long in *S. robinsonii*), and smaller, more deeply lobed corollas (usually less than 1 cm in diameter and lobed 3/4 of the way to the base versus 1–2 cm in diameter and only lobed halfway to the base in *S. robinsonii*). Hul and Dy Phon (2014) described *S. camranhense* as unarmed, but we have seen specimens with a few scattered prickles on the scandent stems. The two species differ in habitat; *S. camranhense* is a plant of coastal dunes, while *S. robinsonii* occurs in coastal forests.
<figure><img src="image_19.png" /><figcaption>**Figure 11.** Distribution of *S. camranhense*.</figcaption></figure>

*Solanum camranhense* is a member of the clade ‘*S. camranhense and relatives*’ of Aubriot et al. (2016a) with *S. nienkui* and *S. putii*; *S. robinsonii* has not been included in any molecular analyses to date, but we expect it to be closely related to these taxa.
**Specimens examined.** See Suppl. materials 1–3.

**6. Solanum capsicoides All., Auct. Syn. Meth. Stirp. Hort. Regii Taur. 64. 1773.**

Fig. 5E–G

Only names based on tropical Asian types listed here; for complete synonymy see Nee 1979; Vorontsova and Knapp 2016.

*Solanum pentapetaloides* Roxb. ex Hornem., Suppl. Hort. Bot. Hafn. 27. 1819. Type. Cultivated in Calcutta (?), *W. Roxburgh s.n.* (lectotype, designated by D'Arcy 1974b, pg. 842, as "type": P-LA [P00357622]).

*Solanum aculeatissimum* Jacq. var. *denudatum* Dunal, Prodr. [A.P. de Candolle] 13(1): 244. 1852. Type. Indonesia. Java: sin. loc., *H. Zollinger 529* (lectotype, designated by Vorontsova and Knapp 2016, pg. 108: G-DC [G00145991, IDC microfiche 800-61.2080:II.6]; isolectotype: G).
*Solanum bodinieri* H.Lév. & Vaniot, Bull. Soc. Bot. France, 55: 206. 1908. Type. China. Hong Kong: Île Verte, 31 Jul 1895, *E.M. Bodinier s.n.* (lectotype designated here: E [E00284479]; isolectotype: A [00077790, fragment]).

*Solanum xanthocarpum* Schrad. & J.C.Wendl. var. *geoffrayi* Bonati, Fl. Indochine 4: 324. 1915. Type. Cambodia. Kampot: “Kampot”, 20 Dec 1903, *C. Geoffray 261* (lectotype, designated here: P [P00055825]; isolectotype: P [P00761034]).

**Type.** Cultivated in Turin, Italy (Torino), *Anonymous s.n.* (holotype: TO [fide Nee 1979]).

**Description.** Vorontsova and Knapp (2016: 108–111); http://www.solanaceae-source.org/solanaceae/solanum-capsicoides.

**Distribution.** *Solanum capsicoides* is widespread but scattered throughout tropical Asia (see Table 2); it is native to Southern South America and is widely adventive and cultivated for ornament.

**Common names.** China. niu qie zi (Zhang et al. 1994).

**Discussion.** *Solanum capsicoides* is a member of the Acanthophora clade along with several other American species introduced to tropical Asia (e.g., *S. aculeatissimum*, *S. mammosum*, *S. viarum*). It can be distinguished from those taxa and from any native species in the region in its absence of any stellate trichomes (all trichomes are simple, but derived from stellate ones, see Levin et al. 2005) and large dark orange berries with winged seeds.

In the description of *S. bodinieri*, Léveillé (1908) did not cite a herbarium or a particular specimen. The herbarium of the French botanist and clergyman Augustin A.H. Léveillé was acquired by the Scottish botanist George Forrest from whence it passed to the Royal Botanic Garden Edinburgh. Vorontsova and Knapp (2016) incorrectly assumed the sheet in E was the holotype. We here lectotypify this name using the specimen at E (E00284479) they cited as holotype.

Bonati (1915) did not cite a specimen or herbarium in his description of var. *geoffrayi*. Hul and Dy Phon (2014) cited “holo-, P!”, presumably referring to one of two sheets of this gathering in P. We select as lectotype the sheet at P with the original label (P00055825) that was presumably the sheet referred to by Hul and Dy Phon (2014).

**Specimens examined.** See Suppl. materials 1–3.

7. *Solanum chrysotrichum* Schltdl., Linnaea 19: 304. 1847.

Figs 5H, 22A

Only names based on tropical Asian types listed here; for complete synonymy see Vorontsova and Knapp 2016.

*Solanum torvum* Sw. var. *pleiotomum* C.Y.Wu & S.C.Huang, Acta Phytotax. Sin. 16(2): 73. 1978. Type. China. Fujian: “Foojow, Tsang Tsien Shen”, 28 Mar 1937, *H. Migo s.n.* (holotype: PE).

**Type.** MEXICO. Michoacan or Jalisco[?]: near Las Trojes, 1825-31, *C.J.W. Schiede 81* (lectotype, designated by Nee 1993, pg. 45: HAL [n.v.]).
**Description.** Vorontsova and Knapp (2016: 120–122); http://www.solanaceae-source.org/solanaceae/solanum-chrysotrichum-0.

**Distribution.** *Solanum chrysotrichum* has been recorded from China, India, Malaysia, and Sri Lanka; it is native Mexico and Central America. Outside of its native range it has been used as a fencing treelet and is widely adventive (see Vorontsova and Knapp 2016).

**Common names.** China. duo lie shui qie (Zhang et al. 1994).

**Discussion.** *Solanum chrysotrichum* is a member of the Torva clade (sensu Stern et al. 2011; Aubriot et al. 2016a). It is morphologically similar to the Torva clade species native to tropical Asia (see Aubriot et al. 2016a for a discussion of this disjunction), but can be distinguished by its rusty pubescence, larger flowers and leathery green, rather than yellow, red or black berries. It is most similar to *S. torvoideum*, but the stellate trichomes of *S. chrysotrichum* are generally longer stalked than those of *S. torvoideum* and are more reddish brown rather than golden brown and the inflorescences of *S. chrysotrichum* are distinctly pedunculate, while flowers of *S. torvoideum* are borne right next to the stem.

In northern India *S. chrysotrichum* forms large stands along disturbed roadsides together with *S. erianthum* D.Don (Brevantherum clade), another widely distributed introduced species. *Solanum chrysotrichum* has often been identified as *S. hispidum* Pers.; that name is a synonym of the Andean species *S. asperolanatum* Ruiz & Pav. In the absence of voucher specimens, references to *S. hispidum* or *S. asperolanatum* in tropical Asian floristic works are difficult to assign to a species.

**Specimens examined.** See Suppl. materials 1–3.

**8. Solanum comitis** Dunal, Prodr. [A. P. de Candolle] 13(1): 345. 1852.
Fig. 12

*Solanum comitum* St.-Lag., Ann. Soc. Bot. Lyon 7: 135. 1880, nom. illeg. superfl.
Type. Based on *Solanum comitis* Dunal.

**Type.** INDONESIA. Java: Sin. loc., 1837, *Without collector* [J.C. von Hoffmannsegg] s.n. (holotype: G-DC [G00131442]; isotype: W [acc. # 1889-0135755]).

**Description.** Habit not known, but probably shrubs or small trees, unarmed or armed with a few tiny prickles hidden by dense pubescence. Stems erect, terete, with a few tiny prickles and densely stellate-pubescent; prickles 1–3 mm long, very sparse if present, broad-based, straight, pale yellowish tan, usually absent; pubescence of mixed sessile and very short-stalked porrect-stellate trichomes, the stalks to 0.5 mm long, the rays 8–10, ca. 0.5 mm long, weak and tangled, the midpoints absent or to 0.4 mm long; new growth densely stellate-pubescent, the trichomes tangled whitish grey in dry material; bark of older stems grey (but only quite young stems seen). Sym podial units difoliate, the leaves geminate, the leaves of pair equal in size and shape or one leaf slightly smaller. Leaves simple, not lobed, the blades 5–11 cm long, 2.5–5 cm wide, ca. 2 times longer than wide, elliptic to narrowly elliptic, chartaceous, strongly
<figure><img src="image_20.png" /><figcaption>**Figure 12.** *Solanum comitis* Dunal. Herbarium specimen (isotype) collected in Indonesia (*Without collector [J.C. von Hoffmannsegg] s.n.*, W [acc. # 1889-0135755]). Photograph credit: CC BY, Naturhistorisches Museum, Wien.</figcaption></figure>
discolorous, unarmed or sometimes sparsely armed along the midrib and major veins with small straight prickles; adaxial surface evenly and sparsely pubescent with erect short-stalked multangulate trichomes, the multiseriate stalks 0.1–0.5 mm long, the rays 6–8, ca. 0.4 mm long and all directly upwards (no clear midpoint), the lamina surface clearly visible; abaxial surface densely pubescent with tangled long-stalked porrect-stellate trichomes, the stalks ca. 1 mm long, the rays 8–10, to 0.6 mm long, thin and delicate; major veins ca. 5 pairs, densely pubescent especially abaxially, with a few tiny prickles abaxially; base acute-attenuate, somewhat oblique; margins entire; apex acute, the tip rounded; petioles 1–1.5 cm long, 1/8–1/4 as long as the leaf blades, sparsely prickly and densely stellate-pubescent, with 1–2 prickles to 2 mm long or more commonly prickles absent, the pubescence of sessile and short-stalked stellate-trichomes like those of the stems. Inflorescences 1–5 cm long, internodal and lateral, unbranched, with 5–15 flowers, only a few flowers open at any one time, densely pubescent with white sessile and short-stalked stellate-porrect trichomes like those of the stems, with 6–8 rays ca. 0.5 mm long and midpoints to 0.4 mm long or absent; peduncle absent and the first inflorescence branches appearing to arise directly from the stem, or to 0.3 cm long, unarmed; pedicels 1.2–1.7 cm long, ca. 1.5 mm in diameter at the base and apex, spreading to erect at anthesis, unarmed, densely stellate-pubescent like the inflorescence axes, articulated at the base; pedicel scars irregularly spaced 1.5–2 mm apart. Buds elongate ellipsoid and somewhat tapering, strongly exserted from the calyx before anthesis. Flowers 5-merous, apparently all perfect, but some distal flowers may be short-styled. Calyx with the tube ca. 3 mm long, conical, the lobes 1.5–2 mm long, 1–2 mm wide, deltate, unarmed and densely white stellate-pubescent abaxially with porrect-stellate trichomes like those of the pedicels. Corolla 2–2.6 cm in diameter, colour not recorded, shallowly stellate, lobed ca. halfway to the base, interpretalar tissue present and abundant, the lobes 6–9 mm long, 6–8 mm wide, deltate, spreading at anthesis, mostly glabrous adaxially but with a few stellate trichomes at the tips, densely stellate-pubescent abaxially with densely tangled sessile trichomes where exposed in bud, these densest at the tips, the interpretalar tissue glabrous or with a few stellate trichomes abaxially. Stamens equal or very slightly unequal, if unequal 3 longer than the other 2; anthers (longer 3) 7.5–8 mm long, ca. 1.5 mm wide, (shorter 2) 5–6 mm long, ca. 1 mm wide, all tapering, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying; filament tube minute, glabrous; free portion of the filaments ca. 0.5 mm long, glabrous. Ovary conical, glabrous; style 10–13 mm long, glabrous; stigma capitate, the surfaces minutely papillose. Fruit a globose berry, several per infructescence, ca. 1.2 cm in diameter, colour not known, pericarp thin and shiny, glabrous; fruiting pedicels 1.6–1.8 cm long, 0.8–1 mm in diameter at the base, 2–2.5 mm in diameter at the apex, erect and slightly woody; fruiting calyx lobes ca. 2.5 mm long, not markedly accrescent, but covering the base of the berry and not reflexed. Seeds 20–50 per berry, ca. 3 mm long, ca. 2.3 mm wide, flattened reniform, pale yellowish tan, the surfaces minutely pitted, testal cells shape not clear. Chromosome number: not known.
<figure><img src="image_21.png" /><figcaption>**Figure 13.** Distribution of *Solanum comitis*.</figcaption></figure>

**Distribution (Fig. 13).** *Solanum comitis* is endemic to the island of Java, Indonesia. No specific localities are recorded on the only two gatherings known of this species.

**Ecology and habitat.** No habitat information has been recorded for *S. comitis*.

**Common names and uses.** None recorded.

**Preliminary conservation status (IUCN 2019).** Data Deficient (DD); known only from two collections of uncertain specific locality. *Solanum comitis* has not been re-collected since the early 19th century, indicating it is certainly of conservation concern. Recollection of this distinctive species and discovery of any precise localities for its occurrence are priorities.

**Discussion.** *Solanum comitis* is a distinctive species, with dense pubescence of multangulate trichomes that dries with a whitish grey tinge. It is superficially similar to the western Australian *S. lasiophyllum* Dunal with dense whitish grey pubescence but differs from that species in its smaller flowers that are probably all hermaphroditic, smaller berries and completely different habitat (tropical versus dry and seasonal). Its relationships are not known, but in the inflorescence, flower and fruit morphology *S. comitis* resembles members of the Torva clade that occur in the Asian tropics (e.g., *S. poka*, *S. pseudosaponaceum*) and we suspect it is a member of that group. Re-collection of this species is a priority.

Although the type specimen is attributed to J.C. Graf van Hoffmansegg, he never actually collected in Java, but rather employed a friend who made natural history collections for him (van Steenis-Kruseman 1985).

**Specimens examined.** See Suppl. materials 1–3.
9. *Solanum cordatum* Forssk., Fl. Aegypt.-Arab. 47. 1775.
Fig. 14

*Solanum gracilipes* Decne., Voy. Inde [Jacquemont] 4(Bot.): 113, t. 119. 1844. Type.
India. "India Borealis Occidentalis", *V. Jacquemont* 63 (holotype: P [P00054212]).

*Solanum sabeorum* Deflers, Bull. Soc. Bot. France 43: 122. 1896. Type. Yemen. N side of Mount Nakhai, Bilad Fodhli, 800 m, 31 Mar 1890, *M. Deflers* 488 (lectotype, designated by Vorontsova and Knapp 2016, pg. 127: P [P00051784; isolectotypes: K [K000441136], P [P00051784, P00051785, P00051786]]).

*Solanum darassumense* Dammer, Bot. Jahrb. Syst. 38: 57. 1905. Type. Somalia. Arussi-
Galla, Darassuma, 900 m, Apr 1900, *H. Ellenbeck* 2024 (lectotype, designated by
Vorontsova and Knapp 2010, pg. 1596: GOET).

*Solanum obbiadense* Chiov., Boll. Soc. Bot. Ital. 1925: 106. 1925. Type. Somalia. "Sultanate of Obbia, Biomal", 2 May 1924, *N. Puccioni & J. Stefanini* 1061 [605] (neotype, designated by Vorontsova and Knapp 2016, pg. 127: FT [FT003066]).

*Solanum nummulifolium* Chiov., Boll. Soc. Bot. Ital. 1925: 107. 1925. Type. Somalia.
"Sultanate of Obbia, Biomal", 2 May 1924, *N. Puccioni & J. Stefanini* 551 [605]
(neotype, designated by Vorontsova and Knapp 2016, pg. 127: FT [FT003065]).

**Type.** YEMEN. Naquil Khailan between Beui Harath and Nehm, NE of Sana'a, 2400 m, 12 May 1978, *J.R.I. Wood* 2327 (neotype, designated by Wood 1984, pg. 136: K [K000441137]; isotype: BM [BM000942294]).

**Description.** Scandent, sometimes erect herb to shrub, 0.3-1 m, unarmed or prickly. Young stems slender, creeping to ascendent, glabrescent, unarmed or sparsely prickly, the pubescence of multangulate, sessile trichomes visible to the naked eye as white dots, the rays 12-18, up to 0.1(-0.15) mm long, the midpoints reduced to a globular gland, the prickles, if present, 0-4 mm long, 0.1-2(-6) mm wide at the base, straight, sometimes slightly reflexed to curved, perpendicular to the stem, pale yellow to brown; bark of older stems glabrous, dark brown or dark grey to black. Sympodial units difoliate, not geminate. Leaves simple, entire, the blades 0.7-1.5(-3) cm long, 0.7-1.3(-3.5) cm wide, 1(-1.5) times longer than wide, orbicular, sometimes ovate, membranous, drying concolorous, yellowish green, glabrescent on both surfaces, with porrect, sessile, sometimes stalked trichomes, the stalks to 0.1 mm long, the rays 8-16, 0.05-0.1(-0.15) mm long, the midpoints reduced or a mere bump, unarmed on both surfaces; the primary veins not visible or 2-4 pairs, the tertiary venation not visible to the naked eye; base cordate to attenuate; apex rounded to acute; petiole 0.2-1.3 cm long, 1/3 as long to equal in length to the leaf blade, narrowly winged to almost filiform, sparsely stellate-pubescent, unarmed. Inflorescences apparently lateral, 1.5-4 cm long, unbranched, with 1(-2) flowers, 1(-2) flowers open at any one time; peduncle absent; pedicels 0.5-3 cm long, erect, filiform, protruding beyond the leaves, articulated at the base, moderately stellate-pubescent to glabrescent, unarmed; pedicel scars spaced 1-4 mm apart. Buds narrowly ellipsoid, the corolla strongly exserted from the calyx before
<figure><img src="image_22.png" /><figcaption>**Figure 14.** *Solanum cordatum* Forssk. Herbarium specimen collected in India (Badami 114, E00757243). Photograph credit: Royal Botanic Garden Edinburgh.</figcaption></figure>
anthesis. Flowers 4-5-merous, apparently all perfect. Calyx 2-4 mm long, the lobes
0.5-2 mm long, ca. 1 mm wide, deltate to narrowly deltate, apically obtuse to acumi-
nate, sparsely stellate-pubescent, unarmed. Corolla 0.9-1.6 cm in diameter, mauve to
purple, stellate, lobed 2/3-4/5 of the way to the base, the lobes 3-6.5 mm long, 1.2-2
mm wide, deltate, reflexed or spreading, stellate-pubescent abaxially, the trichomes por-
rect, sessile, the rays 8-15, up to 0.1 mm long, the midpoints shorter than the rays or
reduced to bulbous base. Stamens equal; filament tube ca. 0.1 mm long; free portion
of the filaments 0.5-0.7 mm long; anthers 3-5 mm long, yellow, spreading, tapering,
poricidal at the tips, the pores distally directed. Ovary glabrous or with 1-2 stellate tri-
chomes near the apex; style 0.8-0.9 cm long, filiform, curved, glabrous. Fruit a globose
berry, 1(-2) per infructescence, 0.6-0.8 cm in diameter, the pericarp thin, glabrous, red
at maturity; fruiting pedicels 1.5-3.5 cm long, 0.3-0.4 mm in diameter at the base,
1.5-2 mm in diameter at the apex, herbaceous, pendulous, unarmed; fruiting calyx
weakly accrescent, elongating to 3-5 mm long, covering 1/4-1/3 of the mature fruit,
unarmed. Seeds ca. 10-20 per berry, 1.8-3 mm long, 1.5-2.2 mm wide, flattened-reni-
form, dark brown to almost black, the testal cells somewhat sinuate in outline. Chromo-
some number: n = 12, 2n = 24 (Kumar and Subramaniam 1987, as *S. gracilipes*).

**Distribution (Fig. 15).** Solanum cordatum occurs from northeastern Africa and the Arabian Peninsula to Pakistan and western India (Punjab, Gujarat, Maharashtra). The record of S. cordatum from Tamil Nadu (Ramachandran and Viswanathan 2010) is based on mis-identified specimens of S. wightii.

**Ecology and habitat.** Solanum cordatum occurs in grassland, bushland, and open woodland on silty, sandy, or stony soil; low elevations (not recorded for India, from sea level to 1,500 m fide Vorontsova and Knapp 2016).

**Common names and uses.** None recorded from the region (see Vorontsova and Knapp 2016 for Africa).

**Conservation status (Knapp 2021a).** Solanum cordatum has been formally assessed as a species of Least Concern (LC; https://www.iucnredlist.org/species/186619213/186619254).

**Discussion.** Solanum cordatum appears to be much less commonly collected in western India than is the very similar and sympatric *S. forskalii*. It differs from *S. forskalii* in its compact multangulate stem pubescence of trichomes with many very short (<0.1 mm long) rays, *S. forskalii* has porrect-stellate trichomes with fewer rays that are marginally longer (> 0.15 mm long); stems of *S. cordatum* appear white dotted from the stubby trichomes. Leaf petioles of *S. cordatum* are decurrent and narrowly winged, while leaves of *S. forskalii* are distinctly petiolate. The calyx lobes of *S. cordatum* are longer and narrower than those of *S. forskalii*, while anthers are shorter in *S. cordatum* (3-5 mm versus 4.5-7 mm).

In eastern Africa, *S. cordatum* is deciduous in the dry season, growing opportunis-
tically during times of moisture (Vorontsova and Knapp 2016). This may be part of the
reason for its relatively fewer collections in India than *S. forskalii*; this species has more
robust leaves that are not deciduous. Wood (1997) suggested that *S. cordatum* was an
"Indian species which extends west to Yemen but is only found in Africa in Somalia."
It is indeed found only in the Horn of Africa (Somalia, Ethiopia, and northern Kenya).
<figure><img src="image_23.png" /><figcaption>**Figure 15.** Distribution of *S. cordatum*.</figcaption></figure>

Ramachandran and Viswanathan (2010) reported *S. cordatum* from Sethukadai in the Namakkal District of Tamil Nadu, far from its known range in India. This report is based on mis-identified specimens of *S. wightii*; the description in Ramachandran and Viswanathan (2010) appears to be a mixture of elements from published descriptions of *S. cordatum* and the actual specimens of *S. wightii* they used as their new record.

**Specimens examined.** See Suppl. materials 1–3.

**10. Solanum cyanocarphium Blume, Bijdr. Fl. Ned. Ind. 13: 700. 1826.**

Figs 1D, 4E, 16

*Solanum sarmentosum* Nees, Trans. Linn. Soc. London 17(1): 58. 1834, nom. il- leg., non *Solanum sarmentosum* Lam., 1794. Type. Malaysia. Penang: Sin. loc., 1822, *N. Wallich s.n.* [Wallich Catal. 2628f] (lectotype, designated here: GZU [GZU000255826]; isolectotype: BM [BM000886340], K-W [K001116668]).

*Solanum bullatorugosum* Dunal, Prodr. [A. P. de Candolle] 13(1): 236. 1852. Type. Indonesia. Java: Sin. loc., *H. Zollinger 1018* (lectotype, designated here: G-DC [G00145849]; isolectotypes: G [G00301680], P [P00369075, P00369076]).
*Solanum maingayi* Kuntze, Revis. Gen. Pl. 454. 1891. Type. Malaysia. Malacca: Sin. loc., *A.C. Maingay* 1158 (lectotype designated by Turner 1998, p. 40, as "holotype": K [K001080494]; isolectotype: LAE [acc. # 229591]).

*Solanum sparsiflorum* Elmer, Leafl. Philipp. Bot. 5: 1838. 1913, nom. illeg., non *Solanum sparsiflorum* Dammer, 1912. Type. Philippines. MIMAROPA: "Puerto Princesa (Mount Pulgar), Province of Palawan, Island of Palawan", May 1911, A.D.E. Elmer 13157 (lectotype, designated here: GH [00077851]; isolectotypes: BISH [BISH1005088], BM [BM000778206], CAL [acc. # 316497], E [E00273861], F [acc. # 384070, v0073463F], G [G00343321], HBG [HBG511492], K [K000195917], L [L0003665], LAE [acc. # 229593], LE, MO [acc. # 706769, MO-2289036], NY [00172293], P [P00379711], W [acc. # 1913-0005906], U [U0113978], US [00027804, acc. # 873055]).

*Solanum thorelii* Bonati, Bull. Soc. Bot. Genève, 1913, sér. 2, 5: 310. 1914. Type. Vietnam. Tây Ninh: "Caï Cong, environs de village", 1862, *C. Thorel* 1419 (lectotype, designated here: P [P00054148]; isolectotypes: P [P00054149, P00054150]).

*Solanum sakhanii* Hul, Fl. Photogr. Cambodge 522. 2013. Type. Cambodia. Sihanoukville: "Sihanoukville", 3 May 2008, K.C. Cheng et al. CL929 (holotype: P [P00836398]; isotypes: P [P00836399, P00836400]).

**Type.** INDONESIA. Java: West Java [“in oryzetis siccis montium Seribu” Curug Seribu near Bogor; from protologue], *C.L. Blume* s.n. (lectotype, designated here: L [L0003630]).

**Description.** Herbs to small shrubs, creeping over the ground, to 1 m tall, armed. Stems decumbent, terete, black to dark brownish, prickly and sparsely stellate-pubescent; prickles to 5 mm long, to 2.5 mm in diameter at the base, straight or curved at the tip, awl-shaped to deltate, flattened, pale yellow in dry material, tan or purplish black in live plants, glabrescent; trichomes porrect-stellate, sessile to stalked, the stalks to 0.1 mm long, the rays 4–7, 0.1–0.4 mm long, the midpoints absent or to 0.4 mm long, sometimes purplish black in live plants; new growth moderately to densely stellate-pubescent, light green in dry material; bark of older stems brownish grey, sparsely stellate-pubescent. Sympodial units plurifoliate, the leaves usually not geminate. Leaves simple, more or less deeply lobed, the blades 4.5–9 cm long, 2–5 cm wide, ca. 2 times longer than wide, elliptic to ovate, chartaceous, slightly discolorous, moderately prickly with 3–7 prickles per leaf side, the prickles to 1 cm long, to 1 mm wide at the base, straight at the tip, awl-shaped, conical, pale yellow in dried material sometimes purplish black in live plants, glabrous; adaxial surface mid-green, moderately stellate-pubescent, the stellate trichomes porrect, sessile to stalked, the stalks to 0.1 mm long, the rays 3–5, 0.1–0.4 mm long, the midpoints to 1 mm long, 2–3 times longer than the rays; abaxial surface light green, moderately stellate-pubescent with trichomes like those of the adaxial surface; major veins 4–5 pairs, drying dark; base cuneate to truncate; margins shallowly to deeply lobed, the lobes 1–4 on each side, 0.5–1 cm long, deltate to oblong, apically rounded, the sinuses extending up to halfway to the midrib; apex rounded to acute; petiole 0.7–2.2 cm long, 1/8–1/5 of the leaf
<figure><img src="image_24.png" /><figcaption>**Figure 16.** *Solanum cyanocarphium* Blume **A** herbarium specimen collected in Vietnam in 1929 (*Lichy* 18, P00055844) **B** detail of the leaves and prickles (field photograph, unvouchered, Vietnam) **C** detail view of a flower (field photograph, unvouchered, Vietnam) **D** detail view of a fruit (field photograph, unvouchered, Vietnam). Photograph credits: **A** CC-BY, Muséum national d'Histoire naturelle, Paris **B–D** M. Nuraliev.</figcaption></figure>

blade length, moderately stellate-pubescent, armed with 1–4 prickles like those of the blades. Inflorescences 1.5–3.5 cm long, apparently lateral, unbranched, with ca. 1–4 flowers, 1–2 flowers open at any one time, sparsely to moderately stellate-pubescent with trichomes like those of the stems but with longer midpoints, unarmed; peduncle 0–8 mm long, unarmed; pedicels 0.5–2 cm long, ca. 0.5 mm in diameter at the base, ca. 1 mm in diameter at the apex, spreading to erect to somewhat nodding at anthesis, unarmed or with 1–11(–16) prickles, moderately stellate-pubescent with trichomes like those of the inflorescence axes, articulated at the base; pedicel scars spaced 0.5–6(–18) mm apart. Buds globose to oval, strongly included in the calyx lobes. Flowers 5-merous, apparently all perfect. Calyx with the tube 2–4 mm long, campanulate, the lobes 2–5 mm long, 1–1.5 mm wide, narrowly deltate, apically acute, densely prickly
and stellate-pubescent abaxially with numerous prickles and trichomes like those of the pedicels but with shorter midpoints. Corolla 1–1.5 cm in diameter, white or purple, stellate, lobed ca. 1/2 of the way to the base, the lobes 3–6 mm long, 2–3 mm wide, deltate, spreading or somewhat campanulate and erect (not spreading and perpendicul lar to the pedicel) at anthesis, glabrous adaxially, moderately to densely stellate pu bescent abaxially, the trichomes often purple-tinged. Stamens equal; anthers 3–5 mm long, ca. 0.5 mm wide, connivent, tapering, orange, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying; filament tube minute, gla brous; free portion of the filaments ca. 1 mm long, glabrous. Ovary conical, minutely glandular-puberulent; style ca. 5 mm long, slender, curved at the apex, glabrous; stigma capitate, the surface minutely papillate. Fruit a globose berry, 1–4 per infructescence, 1–1.6 cm in diameter, red when mature, the pericarp thin and smooth, glabrous; fruiting pedicels 2.5–4 cm long, 0.5–1 mm in diameter at the base, 1–1.5 mm in diameter at the apex, woody, deflexed and nodding, unarmed or with 1–10 prickles; fruiting calyx lobes elongating to 1.3 cm long, 1/2–3/4 the length of the mature fruit, the tips slightly reflexed, usually completely enclosing at least the lower half of the berry, with 6–17(–24) prickles, these often purplish black. Seeds 85–170 per berry, 1.75–2 mm long, 1.5–2 mm wide, flattened reniform, dull yellow, the surface minutely pitted, the testal cells sinuate in shape. Chromosome number: not known.

**Distribution (Fig. 17).** *Solanum cyanocarphium* is widely distributed from south-eastern Indochina to western Malay Archipelago (Borneo, Java, Sumatra and south Philippines).

**Ecology and habitat.** *Solanum cyanocarphium* has been found growing on limestone, in riparian and secondary tropical forests as well as in open degraded vegetation; from 10 to 1,000 m elevation.

**Common names and uses.** Cambodia. plone lane [Khmer] (*Chassagne 138*), trâp krab [Khmer] (Hul and Dy Phon 2014); Indonesia. North Sumatra: tioeng (*Toroes 1639*), teroeng oetan (*Toroes 2926*); Malaysia/Singapore. tërong puyoh, tërong tikus, tërong pipit (all meaning “little brinjal”, Burkill 1935); Vietnam. Đông Nai: blou xit [Mnong] (*Pierre s.n.*), cà co [Vietnamese] (*Pierre s.n.*).

*Solanum cyanocarphium* is said to have edible berries (*Cuadra A1010*) and the juice is drunk for fever (Burkill 1935). Burkill (1935) also records its use to improve the appetite of elephants.

**Preliminary conservation status (IUCN 2019).** Least Concern (LC); EOO 3,563,723 km² (LC), AOO 92 km² (EN). Historical collections of *Solanum cyanocarphium* suggest that this species is widely distributed but absence of recent collections from large areas of the historical range suggests it may merit conservation concern because of the increasing anthropogenic alteration of natural habitat throughout lowland and coastal tropical Asia (Wikramanayake et al. 2002).

**Discussion.** *Solanum cyanocarphium* is a weakly climbing shrub to vine that scrambles over vegetation with hooked prickles; most specimens are quite thin-stemmed and somewhat scrappy. It is superficially similar to *S. procumbens* but differs from it in the strongly accrescent and spiny fruiting calyx (not accrescent in *S. procumbens*),
<figure><img src="image_25.png" /><figcaption>**Figure 17.** Distribution of *S. cyanocarphium*.</figcaption></figure>

larger prickles on stems and leaf blades, deeply lobed leaves (leaves usually entire in *S. procumbens*) and larger and many seeded berries. The accrescent calyx in fruit is similar to that of *S. involucratum*, but that species is more robust and has pubescent, rather than glabrous berries. Hul and Dy Phon (2014) suggested that *S. cyanocarphium* was introduced to Indochina but described what we recognise as a synonym (*S. sakhanii*) as new; we consider *S. cyanocarphium* to be native across tropical Asia where it occurs.

Aubriot et al. (2016a) included *S. cyanocarphium* in a clade called ‘S. cyanocarphium + S. sakhanii’; subsequent examination shows that the two taxa are synonyms (see above), not surprising given the very short branch lengths (Aubriot et al. 2016a).

The Blume specimen in L (L0003630) we have selected as the lectotype of *S. cyanocarphium* is the only one we have found that corresponds to the protologue and is likely to have been the original material that Blume used.

Nees van Esenbeck (1834) only cited a Wallich catalogue number in the protologue of *S. sarmentosum*, but no herbarium. The Solanaceae from his own herbarium are now held at the herbarium (GZU) of the University of Graz (Stafleu and Cowan 1981) and we have selected the specimen there (GZU000255826) as the lectotype, it has flower and fruit and an annotation “S. sarmentosum” in Nees van Esenbeck’s hand.

The protologue of *S. bullatorugosum* (Dunal 1852) cites two specimens at G; we have selected the more complete sheet at G-DC (G00145849) with both flowers and fruits as the lectotype.

The collection cited in the protologue of *S. sparsiflorum* (Elmer 1913) without specification of any herbarium (*Elmer 13157*) is represented in many collections; we have chosen that at GH (0007785) as the lectotype because it is the duplicate best matching the protologue and has both flower and mature fruit. Hul and Dy Phon (2014) cited a sheet in PNH as “holo-, PNH” but this does not constitute effective lectotypification.
Hul and Dy Phon (2014) cited a holotype at P for *S. thorelii*, but no herbarium was cited in the original protologue (Bonati 1914). We select here the best preserved of the three duplicates of *Thorel 1419* held at P (P00054148) as the lectotype.

**Specimens examined.** See Suppl. materials 1–3.

**11. Solanum deflexicarpum C.Y.Wu & S.C.Huang, Acta Phytotax. Sin. 16(2): 73. 1978.**

Fig. 18

*Solanum indicum* L. var. *recurvatum* C.Y.Wu & S.C.Huang, Acta Phytotax. Sin. 16(2): 73. 1978. Type. China. Yunnan: Dali, "Bohai city [transl. from the label]", 21 Feb 1957, *Yunnan expedition 5005* (holotype: KUN [KUN184304]; isotypes: IBK [IBK00241973], IBSC [IBSC0004706], PE [PE00031389, PE02079736], SZ [SZ00254985, SZ00254997]).

**Type.** CHINA. Yunnan: "Xiangping Mountain, Xishou [transl. from protologue]", 29 Aug 1947, *G. Feng* 11429 (holotype: KUN [KUN484279]; isotypes: A [A00310057], PE [PE00730648], WUK [WUK0194818]).

**Description.** Shrubs to 2 m tall, unarmed or rarely sparsely armed. Stems erect, terete, moderately stellate-pubescent; prickles, if present, to 5 mm long, to 3 mm wide at the base, broad-based, curved, pale yellowish tan, sparsely stellate-pubescent near the base; pubescence of sessile to very short-stalked porrect-stellate trichomes, the rays 5–7, 0.1–0.4 mm long, the midpoints absent or to 0.5 mm long; new growth densely stellate-pubescent, the trichomes white and tangled, soon deciduous and the stems glabrate; bark of older stems greyish brown to grey. Sympodial units difoliate, the leaves geminate, or not geminate, the leaves of a pair equal in size and shape. Leaves simple, shallowly lobed, the blades 5–11 cm long, 2.5–7.5 cm wide, ca. 2 times longer than wide, elliptic, chartaceous, discolorous, unarmed or sparsely armed along the midrib and major veins with small curved prickles; adaxial surface evenly and sparsely to moderately stellate-pubescent with white-cream sessile porrect trichomes, the rays 4–6, 0.1–0.2 mm long, the midpoints 0.5–1.3 mm long; abaxial surface with similar sessile porrect-stellate trichomes, but with some short-stalked stellate trichomes with stalks to 0.5 mm and longer rays to 0.5 mm long; major veins 3–4 pairs, densely pubescent especially abaxially; base abruptly truncate, somewhat oblique; margins shallowly lobed, the lobes 3–4 on each side, 0.3–1 cm long, broadly deltate, apically rounded, the sinuses less than halfway to the midrib; apex acute; petioles 1–2 cm long, 1/4–1/2 as long as the leaf blades, sparsely prickly and moderately pubescent, the prickles 0–3, like those of the stems, the pubescence of sessile stellate-trichomes like those of the stems. Inflorescences 1–3 cm long, internodal and lateral, unbranched, with 5–10 flowers, only 1 or 2 flowers open at any one time, pubescent with sessile stellate-porrect trichomes like those of the stems, with 4–6 rays ca. 0.2 mm long and midpoints to 0.5 mm long, unarmed or with a few small prickles to 3 mm long; peduncle 0.1–0.8 cm long, unarmed; pedicels 0.35–0.5 cm
<figure><img src="image_26.png" /><figcaption>**Figure 18.** *Solanum deflexicarpum* C.Y.Wu & S.C.Huang **A** herbarium specimen collected in China in 2007 (*Knapp et al. 10130*, BM001019378) **B** detail of a fertile branch (*Knapp et al. 10130*, China) **C** detail view of a flower (*Knapp et al. 10130*, China) **D** detail view of an infructescence (*Knapp et al. 10130*, China). Photograph credits: **A** CC-BY, © copyright The Trustees of the Natural History Museum, London **B–D** S. Knapp.</figcaption></figure>

long, 0.5–1 mm in diameter at the base, ca. 1 mm in diameter at the apex, spreading and slightly nodding at anthesis, unarmed or with a few small prickles to 1 mm long, densely stellate-pubescent like the inflorescence axes, articulated at the base; pedicel scars irregularly spaced 3–4 mm apart. Buds ellipsoid and somewhat tapering, strongly exerted from the calyx before anthesis. Flowers 5-merous, apparently all perfect, but some distal flowers may be short-styled. Calyx with the tube 2–2.5 mm long, conical, the lobes 1–2 mm long, ca. 1 mm wide, deltate, unarmed or with a few small prickles to 3 mm long and densely stellate-pubescent abaxially with sessile porrect-stellate trichomes like those of the pedicels. Corolla 0.8–1 cm in diameter, white, deeply stellate, lobed 3/4 of the way to the base, interpetalar tissue present, the
lobes 4–4.5 mm long, 2–2.5 mm wide, deltate, spreading at anthesis, mostly glabrous adaxially but with a few stellate trichomes at the tips, densely stellate-pubescent abaxially with densely tangled sessile trichomes where exposed in bud, these densest at the tips. Stamens equal; anthers 3–4 mm long, ca. 2 mm wide, slightly tapering, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying; filament tube minute, glabrous; free portion of the filaments ca. 0.5 mm long, glabrous. Ovary conical, glabrous; style 5–6 mm long, glabrous; stigma capitate, the surfaces minutely papillose, bright green in live plants. Fruit a globose berry, several to many per infructescence, 1–1.2 cm in diameter, orange-red when ripe, the pericarp thin and shiny, glabrous; fruiting pedicels 0.8–1 cm long, 1–1.2 mm in diameter at the base, ca. 2 mm in diameter at the apex, somewhat woody, sharply deflexed and nodding, unarmed or with small prickles; fruiting calyx not accrescent, the lobes often breaking off. Seeds 50–60 per berry, 2–3 mm long, 2–3 mm wide, flattened reniform, pale tan or yellowish brown, the surfaces minutely pitted, the testal cells with sinuate margins. Chromosome number: not known.

**Distribution** (Fig. 19). *Solanum deflexicarpum* is endemic to China (Yunnan province) and only known from few collections; potentially also present in northeastern Myanmar (*Andrews.n.* collected in 'Poneshee' close to the boarder with Myanmar).

<figure><img src="image_27.png" /><figcaption>**Figure 19.** Distribution of *S. deflexicarpum*.</figcaption></figure>
**Ecology and habitat.** *Solanum deflexicarpum* grows in open vegetation and roadsides in semideciduous tropical forests, from 1,255 to 1,500 m elevation.

**Common names and uses.** China. ku ci (Zhang et al. 1994); Yunnan: ku ci, wan bing ci tian qie (pedicel curved and spiny, high altitude) [Mandarin] (Feng 11429).

**Preliminary conservation status (IUCN 2019).** Near Threatened (NT). EOO (65,755 km²); AOO (16 km²). *Solanum deflexicarpum* occurs over a relatively wide range, but there are very few collections; the paucity of collections suggest that the species is of some conservation concern, meriting further study.

**Discussion.** *Solanum deflexicarpum* is morphologically similar to the sympatric and very widespread *S. violaceum* and to the Indian endemics *S. hovei* and *S. multiflorum*; in the analyses of Aubriot et al. (2016a) it is part of a monophyletic group with those species. It differs from *S. violaceum* in its condensed inflorescences with white rather than violet flowers and strongly down-curved fruiting pedicels; the fruiting pedicels of *S. violaceum* are more spaced, straight and are strongly spreading from the axis. *Solanum deflexiflorum* differs from *S. hovei* in its recurved fruiting pedicels (straight in *S. hovei*) and truncate, oblique (versus attenuate) leaf bases. The inflorescences of *S. multiflorum* are similarly condensed, but *S. deflexicarpum* differs from that species in its more compact trichomes, fewer flowers per inflorescence, and its distribution in southern China.

**Specimens examined.** See Suppl. materials 1–3.

**12. Solanum dunalianum Gaudich., Voy. Uranie 448. 1828.**

Fig. 20

*Solanum pulvinare* Scheff., Ann. Jard. Bot. Buitenzorg 1: 39. 1876, as "*pulvinaris*". Type. Indonesia. West Papua: Ajambori, near Doré [Dorei Bay], *J.E Teijsmann s.n.* [7854] (lectotype designated by Symon 1985, pg. 129: BO [acc. # 1324393]; isolectotype: MEL [MEL0104159]).

*Solanum dunalianum* Gaudich. var. lanceolatum Witasek, Repert. Spec. Nov. Regni Veg. 5: 166. 1908. Type. Papua New Guinea. East New Britain: "Vulcanes Kaia" [volcano Kaia], Sep 1905, *K. Rechinger & L. Rechinger 4821* (lectotype designated by Symon 1985, p. 129: W [acc. # 0022303]).

*Solanum dunalianum* Gaudich. var. puberius Bitter, Bot. Jahrb. Syst. 55: 72. 1919. Type. New Guinea. East Sepik: "Kaiser-Wilhelmsland, Hauptlager Malu" [base camp near present-day town of Ambunti], *C.L. Ledermann 10718, 12250* (syn types; type material presumably destroyed at B, see Veldkamp et al. 1988; no duplicates found).

**Type.** INDONESIA. Malaku: Pisang Island, Moluccas Islands, [Dec 1818], *C. Gaudichaud s.n.* (lectotype designated by Bean 2004, pg. 672: P [P00369093]; isolectotype: P [P00369092]).

**Description.** Shrub or small tree to 4 m tall, unarmed or sparsely prickly. Stems erect, unarmed or with a few scattered prickles, glabrous or very sparsely stellate-pubescent;
<figure><img src="image_28.png" /><figcaption>**Figure 20.** *Solanum dunalianum* Gaudich. Herbarium specimen collected in Indonesia in 1917 (*Kaudern* 57, L.4319974). Photograph credit: Naturalis Biodiversity Center.</figcaption></figure>
prickles to 3.2 mm long, to 3.6 mm at the base, straight, narrowly triangular with the sides concave from a wide base, yellow-ferruginous, glabrous; trichomes porrect-stellate, sessile, the rays 6–8, ca. 0.1 mm long, the midpoints shorter to equal to the rays, white to yellow in dry material; new growth glabrous to sparsely pubescent with mixture of stellate and minute glandular trichomes, brownish to black in dry material; bark of older stems dark brownish red, glabrous. Sympodial units difoliate, the leaves geminate. Leaves simple, not lobed, the blades of major leaves 19.7–30 cm long, 9.5–16 cm wide, ca. 2 times longer than wide, ovate to elliptic, the minor leaves half as large as or the same size as the major leaves, subcoriaceous, slightly discolorous, unarmed or with a few prickles along the midrib; adaxial surface densely pubescent with a mixture of numerous minute glandular trichomes and a few porrect-stellate trichomes, the glandular hairs to ca. 0.04 mm long, the stellate trichomes with 6–8 rays, 0.1–0.2 mm long, the midpoints shorter to equal to the rays; abaxial surface moderately pubescent with similar sessile porrect-stellate and glandular trichomes; major veins 12–16 pairs, drying light brownish yellow; base short to very long attenuate, oblique; margin entire or slightly wavy; apex subacute to acute, or short acuminate; petioles 1.5–9 cm long, 1/9–1/6 of the leaf blade length, unarmed or occasionally armed with a few broad-based prickles to 3.9 mm long, to 2.5 mm in diameter at the base, straight, yellow-ferruginous, glabrous or with a few stellate trichomes like those of the blades. Inflorescence to 2 cm, apparently lateral, forked or several-branched, with ca. 50 flowers, 5–15 flowers open at any one time, glabrous to moderately stellate-pubescent on the youngest parts, with sessile porrect trichomes like those of the stems; peduncle 4–12.6 mm long, unarmed; pedicels 5.1–18.6 mm long, 0.3–0.4 mm in diameter at the base, 0.7–1.1 mm in diameter at the apex, erect, unarmed, glabrous to moderately stellate-pubescent with porrect trichomes like the inflorescence but often with longer rays, articulated at the base. Buds fusiform, exerted from the calyx before anthesis. Flowers 4–5-merous, apparently all perfect. Calyx with the tube 1.4–1.9 mm long, campanulate, the lobes 1–1.5 mm long, 1.5–1.8 mm wide, deltate, apex acuminate, the abaxial surface more or less strongly keeled along the midvein, unarmed and glabrous or sparsely stellate-pubescent abaxially with a few porrect-stellate trichomes like those of the pedicels. Corolla 1.8–2 cm in diameter, lavender to violet, stellate, lobed ca. 4/5 of the way to the base, the lobes 8.2–10.5 mm long, 2.5–2.9 mm wide, oblong, spreading at anthesis, densely stellate-pubescent abaxially on parts exposed in bud. Stamens equal; anthers 3.7–5.7 mm long, 0.8–1.3 mm wide, connivent, tapering, yellow, glabrous, poricidal at the tips, the pores directed distally, not elongating to slits with drying. Ovary conical, with a few stellate trichomes; style 6.5–9.5 mm long, filiform, curved towards the apex, glabrous; stigma capitate or slightly bilobed. Fruit a globose berry, several to many per infructescence, 0.8–1.2 cm in diameter, orange to red when mature, the pericarp thin and shiny, glabrous; fruiting pedicels 10.8–18.2 mm long, 0.7–0.9 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, erect; fruiting calyx lobes slightly expending to 1.7 cm long, covering 1/4 of the berry or reflexed, glabrous. Seeds ca. 40 per berry, 1.7–2.5 mm long, 2.5–2.8 mm wide, flattened-orbicular to flattened-reniform, yellow-tan to yellow-ferruginous, the surface minutely pitted, the testal cells pentagonal to sinuate in outline. Chromosome number: not known.
**Distribution (Fig. 21).** *Solanum dunalianum* is found from Sulawesi east through New Guinea and south to the Cape York Peninsula in Queensland, Australia. It has also been collected in Vanuatu and Tonga (Symon 1985).

**Ecology and habitat.** *Solanum dunalianum* typically occurs in disturbed habitats and has been found in secondary rainforest, along roads, in clearings, along streams, and gardens; from sea level to 1,200 m elevation (on New Guinea).

**Common names and uses.** None recorded from the region treated here. Papua New Guinea. Eastern Highlands: gonovise (*Kerenga LAE 56923*); Tonga. Vava'u: polo jongo (*Soakai 1048*).

**Preliminary conservation status (IUCN 2019).** Least Concern (LC). EOO (887,043 km²); AOO (100 km²). *Solanum dunalianum* is at the northeastern edge of its range in tropical Asia, the species is common and widely distributed in New Guinea.

**Discussion.** *Solanum dunalianum* is a species primarily of northern Australia and the island of New Guinea (McClelland 2012) that only just gets into tropical Asia. It was treated as a member of section *Dunaliana* Bitter by McClelland (2012) along with a number of other Pacific species such as *S. viridifolium* Dunal and *S. labyrinthinum* D.McClelland (see McClelland et al. 2020). *Solanum dunalianum* is one of the few species in this group that has been included in molecular analyses (e.g., Aubriot et al. 2016a) and it resolves as part of the 'Sahul-Pacific clade' and member of a group with *S. schefferi* (as *S. lianoides*) and *S. graciliflorum*. Within the area treated here, *S. dunalianum* is distinctive in its branched inflorescence with small red fruits and almost glabrous vegetative parts with very few, if any prickles. Other taxa in the area with several-branched inflorescences are usually densely and variously pubescent (e.g., *S. giganteum*, *S. graciliflorum*, *S. pseudosaponaceum*, *S. torvoideum*).

<figure><img src="image_29.png" /><figcaption>**Figure 21.** Distribution of *Solanum dunalianum*.</figcaption></figure>