Solanum aciculare Sw.
Creators: name: Knapp, Sandra
name: Gouvêa, Yuri F.
name: Giacomin, Leandro L.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Solanales
Solanaceae
Solanum
Solanum aciculare

description: 1.Solanum aciculareSw., Syst. Veg., ed. 15 bis [Roemer & Schultes] 4: 647. 1819
Fig. 2
Solanum kollastrum Gouvêa & Giacomin, PhytoKeys 111: 105. 2018. Type. Brazil. Minas Gerais: Ataléia, povoado de Canaã do Brasil, estrada não pavimentada que liga o município de Ouro Verde de Minas ao povoado de Canaã do Brasil, 18°00'19"S, 41°12'17"W, 313 m alt., Jun 2018, Y. F Gouvêa 280 (holotype: BHCB [BHCB 190863]; isotype: RB [RB 1411895, acc. # 787650]).
Type.
Brazil. “Ex Brasilia” [probably collected in Mucuri River drainage in the State of Bahia, see discussion], no date, G. W. Freyreiss s. n. (lectotype, designated here: S [acc. # S-R- 5812]).
Description.
Shrubs up to 3.5 m, erect, moderately branched. Stems terete, densely glandular-pubescent and prickly, the trichomes porrect-stellate or somewhat multangulate, sessile to long-stalked, the stalks to 1 mm long, the rays 5–20, 2–3 - celled, unequal in length, distally glandular, the mid-point 2–3 - celled, equal to or twice the length of the longest ray, distally glandular, the prickles to 1.7 cm long, 2–3 mm in diameter at the base, straight, acicular or only slightly flattened, yellowish-red, basally somewhat pubescent with stellate trichomes like those of the stems and some small, stalked, uniseriate glandular trichomes; new growth densely glandular pubescent with long-stalked stellate or multangulate trichomes and acicular prickles like those of the stems; bark of older stems greyish-dark brown. Sympodial units difoliate to plurifoliate, the leaves not geminate. Leaves simple, lobed; blades (10) 20–42 cm long, (8) 20–38 cm wide, ca. 1–1.2 times as long as wide, broadly elliptic to broadly ovate, membranous, discolorous, prickly on both surfaces along the veins, the prickles to 1 cm long, straight; adaxial surface densely glandular pubescent, the lamina always visible, the larger trichomes porrect-stellate or multangulate, short- to long-stalked, the stalks to 1 mm long, the rays 4–11, unequal in length, eglandular and 1 - celled or 2–3 - celled and gland-tipped, the mid-points 2–3 - celled, usually longer than the rays, these mixed with smaller sessile to short-stalked porrect-stellate eglandular trichomes, the stalks if present to 0.1 mm long, the rays 2–5, 1 - celled, ca. 0.5 mm long; abaxial surface densely glandular-pubescent, the lamina barely visible, the trichomes porrect-stellate to multangulate like those of the adaxial surface, but denser and much more delicate; principal veins 5–7 pairs; sparsely to moderately armed on both surfaces, the prickles 1–1.7 cm long, 1.3–1.8 mm in diameter at the base, straight, somewhat laterally compressed, usually larger abaxially; base cordate, not decurrent, the two major basal lobes 2.5–7 cm long at the longest point, obtuse to rounded, often overlapping each other across the petiole; margins lobed, the lateral lobes 1.5–4.8 cm long, 4–9 cm wide at base, obtuse or rounded or less often acute at the apex, both basal and lateral lobes sometimes with small secondary lobes; apex obtuse or rounded or less often acute; petioles 4.5–19.5 cm long, densely stellate-pubescent with trichomes like those of the stems, usually densely prickly. Inflorescences subopposite the leaves or internodal, 4.5–12 cm long, usually unbranched, rarely forked or trifurcate, with 11–35 flowers, up to 3 open at a time; axes densely glandular-pubescent and prickly, the trichomes porrect-stellate to multangulate, hyaline to yellowish-brown like those of the stems, the prickles ca. 1 mm long, straight, like those of the stems and leaves; peduncle 2.6–6 cm long; pedicel scars generally unequally spaced, closely packed to spaced 2.3 cm apart; pedicels 4.8–18 mm long, densely pubescent and prickly with trichomes and prickles like those of the stem, but these often purple-tinged, articulated at base. Buds ellipsoid to globose-ellipsoid, the corolla ca. halfway exserted from the calyx tube before anthesis, but enclosed in the calyx lobes. Flowers 5 - merous, heterostylous, with basal long-styled co-sexual flowers and functionally staminate short-styled flowers that vary in proportion between inflorescences, the plants andromonoecious. Calyx with the tube 4.5–8.2 mm long, 9.4–15.2 mm in diameter, broadly cup-shaped to somewhat urceolate, inflated, purple-tinged (mainly along the margins and apex of the calyx lobes) to green, armed, densely pubescent with trichomes like those of the stem, but these sometimes purple and with some eglandular rays, the lobes 7.5–15.6 mm long, 6–9 mm wide, triangular, the margins plane to strongly undulate and revolute, the apices acute to caudate. Corolla 2.3–3.9 cm in diameter, purple to lilac or bluish-lilac, white in some stages of development, shallowly stellate to stellate, lobed 2 / 5 to 1 / 2 the way to the base, interpetalar tissue absent, the lobes 10.9–15 mm long, 8.8–13.4 mm wide, deltate to triangular, spreading at anthesis, abaxially glandular stellate-pubescent with trichomes like those of the leaves, adaxially almost glabrous with only a few stellate trichomes sparsely distributed along the veins and near the tips, the apex acute, slightly apiculate. Stamens equal; filament tube 1–2.1 mm long; free portion of the filaments 1.3–2.9 mm long, glabrous; anthers 7.5–10 mm long, 2.8–4.3 mm wide, broadly lanceolate and tapering, connivent, glabrous, yellow, abaxially swollen in the lower half (gibbous) and somewhat papillate, poricidal at the tips, the pores directed distally, slightly extrorse, not elongating to slits with age. Ovary conical to somewhat cupuliform, densely stellate-pubescent and glandular at the apex, becoming glabrous with age, the trichomes porrect-stellate, sessile, 2–7 - rayed, with a 2–4 - celled, eglandular or glandular mid-point longer than the 1 - celled rays; style 13.7–15.9 mm long in long-styled flowers, 1.2–3.7 mm long in short-styled flowers, straight, glabrous; stigma large-capitate to clavate, up to 1.4 mm long in long-styled flowers, the surface papillose, green when fresh. Fruit a globose to somewhat compressed globose berry, 1–1.1 cm long, 1.2–2.3 cm wide, pale green to white, glabrous, but with scattered stellate trichomes at the apex, the pericarp somewhat shiny when dry, the berry almost completely enclosed in the saccate fruiting calyx; fruiting pedicels 1.4–2.2 cm long, 1.5–2 mm in diameter at the base, woody and somewhat deflexed from the weight of the fruit, armed with sparse straight prickles like those of the flowering pedicels; fruiting calyx strongly accrescent and inflated, completely enclosing the berry, the tube 1.6–2.1 cm long, 1.9–3.4 cm in diameter at the widest point, the base somewhat plicate and invaginate, the lobes 1.1–2.2 cm long, 1.3–1.9 cm wide, usually somewhat overlapping, densely glandular-pubescent with porrect-stellate to multangulate trichomes. Seeds ca. 230 per berry, ca. 2 mm long, 2.4 mm wide, flattened-reniform, dark brown, the testal cells sinuate in outline; stone cells absent. Chromosome number: not known.
Distribution
(Fig. 3). Solanum aciculare is endemic to eastern Brazil. Records are mostly concentrated along the Mucuri River watershed, ranging from the Municipality of Teófilo Otoni, in north-eastern Minas Gerais State, to Mucuri on the southern coast of Bahia. A single collection (J. G. Jardim et al. 3151; CEPEC, NY) is known from further north, in Mun. Caatiba of the south-central region of Bahia State.
Ecology.
Solanum aciculare inhabits edges of small forest fragments, especially those at the base or on granitic outcrops (inselbergs) or in disturbed sites near these rock outcrops, such as borders of unpaved roads and pastures. It is also found in herbaceous to arboreal vegetation growing along the Brazilian sandy coastal lowlands (restinga sensu Araújo (1992)), where plants grow in open disturbed areas dominated by grasses and at the edge of forest fragments (Fig. 2 A). Habitats vary from environments subject to periods of drought (e. g. the edge of small seasonal semi-deciduous forest fragments or vegetation islands on inselbergs) to constantly wetter environments, at the edge of coastal evergreen forests, where the climate is under a strong oceanic influence. Plants have been collected from sea level to about 900 m elevation.
Common names and uses.
None recorded.
Preliminary conservation assessment
(IUCN 2020). EOO (38,277 km 2, NT); AOO (56 km 2, EN). Despite the relatively large range of S. aciculare, all collections are from only three broad localities and all are outside protected areas; vulnerability of the habitats in which the species occurs and the small number of localities suggest S. aciculare should be considered Endangered using the criteria B 2 a, b (ii, iii, iv).
Discussion.
The name Solanum aciculare has not been used previously in treatments of Brazilian Solanum (Sendtner 1846) and, until recently, had been considered an ‘ unassigned’ name (Flora e Funga do Brazil 2024). Examination of the type specimen and analysis of the collecting trajectory of Georg Freyreiss (see below or in Taxonomy) make clear that this plant is identical to that described as S. kollastrum (Gouvêa et al. 2018). Sendtner (1846) had not seen the specimen on which S. aciculare was based and his description was of another plant (Sellow s. n.) that he admitted did not completely correspond to Swartz’s description (“ Solano subscandenti non dissimile in unico specimine suppetente a diagnosi Swartziana paullisper recedens. Proferamus descriptionem nostro specimini accomadatam, momenti, quo discrepat Swarztius haud immemores ” - Not dissimilar to Solano subscandens in the only specimen available, departing for a moment from the Swartzian diagnosis. Let us present the description attached to our specimen, the importance of which Swartzius disagrees, not unmindful of it: transl. SK). The specimen described by Sendtner as S. aciculare is S. cordifolium Dunal, a member of the Erythrotrichum clade.
Amongst the species in this group, only S. aciculare and S. sublentum have cordate leaf bases coupled with glandular trichomes throughout the stems and leaves. Decurrent leaf bases of S. aciculare are only seen in the first leaves of the seedlings, with the subsequent leaves gradually changing shape to become cordate and non-decurrent. In contrast, the leaf bases in S. hexandrum and S. stagnale remain decurrent throughout plant development, varying in shape from attenuate to truncate.
Solanum aciculare closely resembles S. sublentum, from which it can be readily distinguished by the robust long-stalked (up to 1 mm) stellate-glandular trichomes with all rays having a glandular distal cell (some rays may lose the glandular cell through breakage or by the disruption of the gland wall) on young stems, petioles and inflorescence axis; trichomes in S. sublentum are usually simple. Solanum aciculare and S. sublentum have very similar floral morphologies, sharing well-developed calyces that are strongly accrescent in fruits, showy purple to lilac corollas and robust anthers. Fruits of S. aciculare are completely enclosed in the accrescent calyx, whereas those of S. sublentum are exposed. Their leaves also resemble each other: both are lobed (with secondary lobes or not), elliptic to ovate (or broadly ovate in S. aciculare) and have cordate bases (varying from truncate to cordate or sagittate in S. sublentum). In the field, S. aciculare has notably larger leaves than those of S. sublentum; however, usually only the apices of the branches are collected, with the fully developed leaves not represented in herbarium material, so this character is often not apparent from herbarium specimens. Although S. aciculare and S. sublentum occur in similar environmental conditions (associated with outcrops or at edges of lowland forests), they have not been observed in sympatry.
Both S. aciculare and S. phrixothrix have densely bristly stems and elongate slender inflorescences. They can be distinguished by the glandular long-stalked stellate pubescence of S. aciculare (versus eglandular bristles and lack of long-stalked stellate trichomes in S. phrixothrix) and flower shape and colour (purple and stellate in S. aciculare versus white and rotate in S. phrixothrix).
The German collector Georg Freyreiss (also sometimes spelled Freyreis), who was principally an ornithologist and Friedrich Sellow, a botanist, travelled and collected in Brazil in the first decade of the 19 th century. Sellow’s botanical collections comprise many hundreds of specimens and were the basis for many new species (Urban 1893; Moraes 2023). In 1815, Freyreiss and Sellow were planning a trip to the north of Rio de Janeiro. They joined forces with Prince Maximilian of Wied, a member of the German aristocracy who was interested in natural history and had been inspired by Baron Alexander von Humboldt to travel to South America, particularly to Brazil (Moraes 2009, 2011). Wied was keen to travel via the, at the time, relatively unexplored coast and, with Freyreiss (Sellow having stayed in what is now the State of Espirito Santo), reached the Rio Mucuri near the border of Espirito Santo and Bahia States, then continued to Salvador in today’s State of Bahia. The type specimen of S. aciculare was probably collected by Freyreiss in the Mucuri River drainage during this voyage.
description: Published as part of Knapp, Sandra, Gouvêa, Yuri F. & Giacomin, Leandro L., 2025, A revision of the endemic Brazilian Solanum hexandrum group (Leptostemonum, Solanum, Solanaceae), pp. 199-259 in PhytoKeys 253 on pages 199-259, DOI: 10.3897/phytokeys.253.138216