Gymnosporia swazica Jordaan 2015, sp. nov.
Creators: name: Jordaan, Marie
name: Van Wyk, Abraham E.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Celastrales
Celastraceae
Gymnosporia
Gymnosporia swazica

description: Gymnosporia swazica Jordaan, sp. nov. (Fig. 1)
Closely related to Gymnosporia buxifolia (Linnaeus 1753: 197) Szyszylowicz (1888: 34), but differs in having glabrous, smooth, yellow capsules. It differs from G. maranguensis (Loesener 1894: 231) Loesener (1908: 303) by having 3- (vs. 2-) valved capsules; and from G. harveyana Loesener (1896: 430), by having a white (vs. orange) aril partially (vs. completely) covering the seed.
Type: — SOUTH AFRICA. Mpumalanga: Nelspruit District, Crocodile River Gorge, along road from Nelspruit to Kaapmuiden, 11 July 2000, Jordaan 3712 (holotype PRE0863219-0!, isotypes K!, NH!).
Gymnosporia sp. D in Schmidt et al. (2002: 348).
Gymnosporia graniticola (ined.) in Loffler & Loffler (2005: 54).
Small tree up to 3 m tall, usually single-stemmed, sometimes multi-stemmed, few-branched with longer branches drooping at ends, glabrous; branchlets angular, green, becoming dark grey, without lenticels. Thorns axillary, slender, up to 15 mm long. Brachyblasts up to 4 mm long. Leaves chartaceous, concolourous; lamina obovate to spathulate, 10–20(–45) × 5–10(–15) mm, apex acute to rounded to emarginate, base tapering into petiole, margin crenate, midrib prominent in lower half when dry, fading towards tip, reticulate venation conspicuous on both sides; petiole very short, almost absent. Inflorescence few-flowered; peduncle ± 2 mm long; pedicels ± 0.5 mm long. Flowers cream. Sepals oblong-lanceolate, ± 1 mm long, apex obtuse. Petals oblong, ± 1.5 mm long, margin fimbriate. Disc narrow, convex, 5- lobed. Male flowers: stamens included, ± 1 mm long; style ± 0.5 mm long; stigma absent. Female flowers: staminodes included, ± 0.5 mm long; style ± 0.5 mm long; stigma 3-lobed. Capsules globose, 3-valved, smooth, green, ripening yellow, 6–10 mm long. Seeds 1–4, dark reddish brown; aril white, partially covering the seed.
Diagnosis and relationships: — Gymnosporia swazica differs from G. buxifolia, in having smaller (usually shorter than 20 mm) chartaceous leaves, and capsules which are smooth, green ripening to yellow and are usually 6–10 mm long. The leaves of G. buxifolia are 25–80 mm long, and the capsules are smaller, usually less than 5 mm long, with the surface rugose and ripening to a finely mottled white-and-brown. With its relatively small leaves densely arranged on the branches, G. swazica superficially resembles G. matoboensis Jordaan (Jordaan & Van Wyk 2006: 520), a species confined to the rocky granite outcrops of the Matobo region in Zimbabwe. G. swazica is glabrous in all parts, whereas G. matobensis has puberulous branches, leaves, inflorescences and capsules. Its affinity also lies with G. maranguensis, which also has smooth capsules, but G. swazica can be distinguished by its smaller leaves (usually shorter than 20 mm) and capsules green instead of red, 3-valved instead of 2-valved and larger, 6–10 mm long. When sterile G. swazica can easily been confused with G. harveyana, which is also one of the few forest species in the genus, but differs in lacking thread-like stipules. When in fruit, G. swazica is easily distinguishable from G. harveyana, the latter which has smooth, pinkish to reddish capsules with seed completely covered by an orange aril, whereas G. swazica has yellowish smooth capsules and a white aril only covering the seed partially. Characters to differentiate among G. swazica and the associated species with which it can be confused, are summarized in Table 1.
Distribution: —Although G. swazica is mainly associated with the Lebombo Mountains in Swaziland, hence the specific epithet, it is also known from scattered localities in South Africa’s Mpumalanga Province (Crocodile River Valley region, east of Nelspruit) and far northeastern part of KwaZulu-Natal (Fig. 2).
Ecology: —The new species grows in small forest enclaves within a fire-maintained savanna matrix known as SVI 3 Granite Lowveld (Mucina & Rutherford 2006). Van Rooyen & Bredenkamp (1996) recognized this vegetation type as Mixed Lowveld Bushveld (elevation 450–600 m), generally a frost-free region with low rainfall (400–800 mm per year) and temperatures between -4°C and 45°C, with an average per annum of 22°C. The substrate is characterized by sandy soils in the uplands and clayey soils with a high sodium content in bottomlands. The geology is granite and gneiss with numerous dolerite intrusions and areas covered by gabbro (Van Rooyen & Bredenkamp 1996). Acocks (1988) considered the climax of this area to be forest. G. swazica grows in forest in shade, on hillsides, in soils derived from granite, often among boulders, close to streams. It is often associated with Diospyros natalensis (Harvey 1863: 7) Brenan (1954: 500) subsp. nummularia (Brenan 1948: 111) Jordaan (2009: 102).
Additional specimens examined (paratypes): — SOUTH AFRICA. Mpumalanga: ± 25 km from Nelspruit to Kaapmuiden, Crocodile’s Poort Mountains, Jordaan 3845 (PRE); KwaZulu-Natal: Lebombo Mountains, Sikulukulu stream, Ward 1507 (NH); Lebombo Mountains, road between Ingwavuma and Josini, P. van Wyk BSA694 (PRE, PRU). SWAZILAND. Stegi District, 14 miles S of Stegi, Compton 30062 (PRE); Blue Jay Ranch, Lebombo Mountains S of Umbuluzi Gorge, 3 miles NNE of Mhlumeni border post, Culverwell 1107 (PRE); Lebombo Mountains, Kemp 706 (PRE); 4 km NE of Tikuba store on road from Siteki to Mambane, Prior 376 (PRE).
description: Published as part of Jordaan, Marie & Van Wyk, Abraham E., 2015, Gymnosporia swazica (Celastraceae), a new species from southern Africa, pp. 296-300 in Phytotaxa 192 (4) on pages 296-299, DOI: 10.11646/phytotaxa.192.4.7, http://zenodo.org/record/13641764