Oxalis hirsutibulba Dreyer, Roets & Oberl., 2014

Roets, F., Oberlander, K. C. & Dreyer, L. L., 2014, New relatives of Oxalis pes-caprae (Oxalidaceae) from South Africa, Blumea 59 (2), pp. 131-138 : 135

1. Oxalis hirsutibulba Dreyer, Roets & Oberl. , sp. nov. — Fig. 2

Type. Bayer 1497 ( NBG), South Africa, Northern Cape, Richtersveld Conservancy, west of Eksteensfontein , 2817 CC, Sept. 1978, flowering .

Geophyte up to 20 cm tall, bright green, densely but finely hairy. Bulb shallow, up to 6 cm long, teardrop-shaped, distinct elongated upper portion between a third and half of bulb length (apical beak), tunics hard, densely hairy, distinctly longitudinally grooved, light brown, often with contractile root. Rhizome brown, up to 20 cm long, hairy to densely hairy, with light brown alternating scales up to 4 mm long. Above-ground stem up to 4 cm long, green, hairy, with 1–2 large (up to 8 mm long) semi-amplexicaul, membranous scales. Leaves 3 –14, bright green, loosely apically congested, hairy; petioles up to 14 cm long, dilated below basal articulation, hairy; leaflets 3, cuneateobcordate to obcordate, up to 3 × 3.5 cm broad, finely hairy on both sides and along margin, distinctly petiolulate, adaxial side glossy along margin. Peduncles 1–7-flowered, densely hairy, as long as to 2.5 times longer than and as thick as petioles. Bracts 2–6, linear, erect, up to 7 mm long, densely hairy, without calli. Pedicels slender, up to 25 mm long. Sepals 5, linear-lanceolate, acute, densely hairy, without calli. Corolla up to 25 mm long, glabrous to sparsely hairy, white, with broad funnel-shaped yellow tube. Petals 5, lobes white, tube yellow, funnel-shaped, densely hairy. Stamens 10, in 3 whorls; 2 whorls per plant, lower whorl 2.5– 4 mm long, middle whorl c. 5 mm long, longest whorl c. 9 mm long; filaments hairy; anthers oval, yellow. Ovary narrowly ovoid, c. 5 mm long, 5-loculed, yellow, densely hairy, up to 13 ovules per locule; styles 5, separate, reciprocally herkogamous with two stamen whorls, short-whorled styles curving outwards between filaments, mid- and long-whorled styles erect, densely hairy. Stigmas green, fimbriate. Fruit capsule cylindrical, hairy, twice as long as sepals. Seed endospermous.

Diagnostic characters — Geophyte with densely hairy vegetative plant body. Bulb tunics light brown, finely grooved, densely hairy and with apical beak. Corolla lobes white, tube yellow. Both morphological characters and DNA evidence distinguish O. hirsutibulba from all known Oxalis species with umbellate inflorescences. It prefers cool, south-facing cliffs, where it grows in loose soil in cracks. Oxalis hirsutibulba flowers from August to September.

Distribution — Only known from three localities in the Northern Cape Province of South Africa. One locality is situated on the southern slopes of the Richtersberg range, another is west of Eksteensfontein, while a third population is known from near Kubus.

Additional specimens examined. SOUTH AFRICA, Northern Cape, Richtersveld Conservancy, southern slopes of Richtersberg , 2817 CA , June 2012, sterile, Dreyer, Roets & Oberlander MO1519 ( NBG, STEU) ; Northern Cape Province, Richtersveld Conservancy,west of Eksteensfontein ,2817 CC , June 2012, sterile, Dreyer, Roets & Oberlander MO1521 a ( STEU); Stellenbosch Botanical Garden , Aug. 2012, cultivated from Dreyer, Roets & Oberlander MO1521 a, origin Northern Cape, Richtersveld Conservancy, west of Eksteensfontein , 2817 CC , June 2012, flowering, Dreyer, Roets & Oberlander MO1521 b ( STEU); Northern Cape Province, Richtersveld Conservancy, Top of Helskloof pass, 2816BD, June 1977, Thombson & Le Roux 101 ( NBG) ; Northern Cape Province, Richtersveld Conservancy, Top of Helskloof pass, 2816BD, Sept. 1975, flowering; Bayer 1507 ( NBG) .

Figures

Fig. 2 a. Typical habitat of Oxalis hirsutibulba in the Richtersveld Conservancy; b. Oxalis hirsutibulba herbarium specimen (Bayer 1507, NBG); c. flower - side view; d. flower - top view; e. leaves - adaxial side; f. leaves - abaxial side; g. bulb. — Scale bars = 1 cm.