Polygala retiefiana Paiva & Figueiredo, 2013

Paiva, Jorge, Figueiredo, Estrela & Smith, Gideon F., 2013, Polygala retiefiana (Polygalaceae), a new species described from South Africa, Phytotaxa 117 (1), pp. 30-34 : 31-33

Polygala retiefiana Paiva & Figueiredo , sp. nov. ( Fig. 1 )

It is distinct from the closely related Polygala garcinii based on its smaller flowers that have asymmetric wing sepals of 8.0– 8.5 mm long (instead of symmetric wing sepals, 8–11 mm long) and a carina of 4.0– 4.5 mm long (instead of 7– 10 mm long).

Type:— SOUTH AFRICA. Free State: Harrismith District, Berg Manyenyeza op die plaas [on the farm] Rensburgskop , 2829 AD, 1800 m elev., 17 January1977, Jacobsz 347 (holotype PRE!) .

Perennial herb, with a woody base. Stems slender, 20–30 cm long, branched, angled, glabrous. Leaves alternate, subsessile (petiole up to 0.5 mm long, glabrous), linear, 8–18 × 0.5–1.0 mm, acute, glabrous. Flowers pinkish, in few-flowered (5–16 flowers), terminal racemes, erect, up to 8 cm long, rachis and peduncle glabrous; pedicels 3–4 mm long, glabrous; bract linear, 2.0– 2.5 mm long, glabrous, persistent; bracteoles linear, ca. 1 mm long, glabrous, persistent. Posterior sepal linear-lanceolate, 4.0 × 1.25 mm, acute, glabrous; wing sepals asymmetrically elliptic, 8.0–8.5 × 5 mm, glabrous; anterior sepals linear-lanceolate, 3 × 1 mm, acute, glabrous, free. Upper petals obovate, 3.0–3.5 × 1.5 mm, unequally bifid; carina 4.0–4.5 × 1.75– 2.0 mm; crest 1.5–2.0 mm long, fimbriate. Stamens 8. Capsule widely-elliptic to almost obovate in outline, 5.0–5.5 × 4 mm, asymmetrically bilobate, glabrous, winged (wing 0.5–0.75 mm wide). Seeds ellipsoid, 2.75– 3.0 × 1.25 mm, sparsely sericeous-pubescent; caruncle 0.5 mm long, long-hairy, with three long appendages, ca. 1.5 mm long.

Distribution and habitat: — Polygala retiefiana is endemic to South Africa, where it occurs in grasslands in summer-rainfall areas, at elevations of up to 1800 m above sea level, around the border of the KwaZulu- Natal and Free State provinces of the country and neighbouring Lesotho ( Fig. 2 ). All the collections of this species recorded to date have been made on the Drakensberg proper, close to and immediately north of the Drakensberg Alpine Centre of Endemism (DAC) as defined by Van Wyk & Smith (2001).

Phenology: —Flowers recorded from October to March, therefore from early to late summer in the Southern Hemisphere.

Conservation status: —This species is represented in PRE by five collections only, the most recent one dating from 1977, which may be an indication of its rarity.

Etymology: —The species is named after Dr Elizabeth Retief (born in Bloemfontein on 11 October 1947) a South African taxonomist who worked at the National Herbarium of South Africa from 1970 to 2010. She co-authored the recently described Polygala sekhukhuniensis Retief, S.J.Siebert & A.E.van Wyk in Siebert et al. (2010).

Additional specimens examined (paratypes): — SOUTH AFRICA. Free State: Harrismith District , 2829 AC , 4 March 1962, Jacobsz 137 ( PRE!) . KwaZulu-Natal: Bergville district, Drakensberg National Park, slopes of Plowman’s Kop , 2828DB, 29 October 1938, Hafstrom & Acocks 822 ( PRE!); Mont-aux-Sources, 2828 DD , 1800 m elev., 4 October 1950, Sidey 2018 ( PRE!); Eastcourt district, Giant’s Castle Game Reserve , Mumden Stream, 2929AB, 1620 m elev., date unrecorded, Trauseld 471 ( PRE!) .

Discussion: — Polygala retiefiana belongs to Polygala sect. Psychanthus [ Rafinesque (1814: 116)] De Candolle (1824: 321). The species included in this section are distributed in southern and southeastern Africa. The main characters distinguishing the section are: flowers in terminal or pseudo-lateral racemes, anterior sepals free, wing sepals large and covering the capsule, upper petals bilobed to subentire and seeds pubescent and carunculate, with the three branches of the caruncle ± the same length.

The specimens of Polygala retiefiana had been previously identified as P.refracta , but the two species are easily distinguishable on account of the terminal racemes of P. retiefiana (as opposed to lateral racemes of P. refracta ), in other words, the secondary fertile branches (with racemes) in P. refracta are much shorter compared to P. retiefiana . Polygala retiefiana appears to be more closely related to P. garcinii , a species also endemic to South Africa, but which is restricted to the winter-rainfall areas of the Western Cape province. Polygala retiefiana differs from P. garcinii in the smaller size of the flowers and shape of the wing sepals. A characteristic feature of the new species is that the caruncle is long-hairy, with three long appendages.

Polygala retiefiana occurs in summer-rainfall areas of South Africa, but it appears to be sparsely distributed, as no recent specimens were found in PRE; the most recent specimen found in the collection dates from 1977. Since the area where the species occurs is well represented in PRE, the lack of recent material of this species may be an indication of its relative rarity.

Figures

FIGURE 1: A. Habit. B. Crest. C. Flower. D. Flower with calyx removed. E. Fruit. F. Seed. A–D from Jacobsz 347; E from Trauseld 471; F from Jacobsz 137.Scale bars: A, 20 mm; B, 0.5 mm; C–E, 2 mm (between C&D); F, 1 mm. Artist: Gillian Condy.

FIGURE 2: Distribution of Polygala retiefiana.