Oxalis magnifolia Dreyer, Roets & Oberlander, 2017

Dreyer, Léanne L., Roets, Francois & Oberlander, Kenneth C., 2017, Two new Oxalis (Oxalidaceae) species, including 5 varieties, from the Richtersveld of South Africa, Phytotaxa 314 (2), pp. 231-240 : 237

Oxalis magnifolia Dreyer, Roets & Oberlander , spec. nov. ( Fig. 4 )

Oxalis magnifolia is characterised by being acaulescent, having broad (> 10 mm), glaucous-green leaflets with a waxy covering, petioles that are thicker than the peduncles, peduncles that bear a single white or yellow flower with a broad funnel-shaped tube, and a bulb that is covered in dark brown, shiny, keeled tunics.

Type:— SOUTH AFRICA. Northern Cape Province, Springbok, south of Steenbokberg, 2917 AD, 13 September 1977, M. B. Bayer 994 (holotype NBG!)

Acaulescent geophyte, up to 150 mm tall, glaucous. Contractile root, if present, not observed. Bulb obovate to elliptical, large, up to 60 × 50 mm, young bulbs with pointed apex; tunics fairly numerous, hard, dark brown, shiny, keel-shaped, glabrous, with acute apices. Rhizome 40–170 mm long, sparsely to densely glandular hairy, covered by smooth, dark brown, papery sheath, with few to many adventitious roots. Above-ground stem absent. Leaves usually very large, 1–3, trifoliolate, with waxy covering. Petiole variable in length, 10–50 mm long, in plants with shorter petioles often resulting in a crowded appearance to the leaflets, slightly thicker to much thicker than peduncles, slightly flattened adaxially. Leaflets prostrate to semi-erect, highly variable in size, up to 50 × 53 mm, non-conduplicate, broadly cuneate-obovate, often purple below, glaucous above, epistomatic, margin sparsely glandular ciliate, often with small round calli towards the margins. Peduncles 1-flowered, up to 150 mm long, thinner and much longer than the petioles, glabrous to sparsely and minutely glandular hairy. Bracts 2, variously positioned on upper half of peduncle, alternate, up to 5 mm long, thread-like, apices obtuse, sparsely glandular, occasionally with calli towards the apex. Flowers white or yellow. Sepals 5, broadly lanceolate to obovate, apices obtuse to subacute, up to 6.0 × 2.5 mm, glabrous to glandular-hairy on margin, often purple-veined, mostly ecallose (type specimen with many small calli on margin). Corolla 17–28 mm long, with short, broadly funnel-shaped tube; petals 5, up to 28 × 15 mm, lamina obovate, apices rounded to truncate, glabrous, often with small round calli near the apex. Stamens 10, in 3 series, 2 series per plant, the shortest level 3.0 mm, the middle level 5.0 mm long and the longest level 8.0 mm long, filaments basally connate, longest filaments with short, blunt teeth, up to 0.5 mm long. Ovary 5-locular, 3.0 mm long, narrowly ovoid, usually ecallose (type specimen with many scattered small calli), glandular hairy; styles 5, separate, in three series with one series per plant, shortest level 3.0 mm long, middle level 5.0 mm long, longest level 8.5 mm long, erect, glandular-hairy; stigma green, fimbriate. Fruit a capsule, slightly longer than sepals, up to 6.0 × 3.5 mm. Seeds without endosperm. Pollen tricolpate, tectum reticulate with intra-luminary bacules clustered along muri. Flowering time April to September.

Etymology:— The name refers to the very large leaves of this species.

Habitat:— This species generally prefers Succulent Karoo vegetation, and has been found growing in both shallow, rocky, clay soils and in deep sandy soils. It prefers full sun, and was collected from both lowland and hilltop localities.

Additional material studied (paratypes):— SOUTH AFRICA. Northern Cape Province, Richtersveld Conservancy, on hill east of Tierhoek Camp Site , 700 m, 18 June 2012, Oberlander, Roets & Dreyer 2012/06-50 ( STEU!) ; Northeast of Tierhoek Camp Site 560 m, 18 June 2012, Oberlander, Roets & Dreyer 2012/06-51 ( STEU!) ; 8 km west of Eksteenfontein , on hill, 640 m, 18 June 2012, Oberlander, Roets & Dreyer 2012/06-53 ( STEU!) ; Tierhoek Camp Site , 520 m, 18 June 2012, Oberlander, Roets & Dreyer 2012/06-56 ( STEU!) ; Steinkopf, on farm road north of Steinkopf-Port Nolloth road, 880 m, 1 July 2015, Oberlander, Roets & Dreyer 2015/07-01 ( STEU!) ; Klein Hellskloof Pass, between Vioolsdrif and Eksteenfontein , 480 m, 16 June 2012, Oberlander, Roets & Dreyer 2012/06-29 ( STEU!) ; Springbok, Steenbokberg , 2917 AD, 13 September 1977, Bayer 995 ( NBG!) ; Vioolsdrif, Skouerfontein , NNW of Eksteenfontein, 2817 CC, 28 September 1978, Bayer 1496 ( NBG!) ; Vioolsdrif , 2 km N of Eksteenfontein, 2817CD, 10 August 1979, Perry 1068 ( NBG!) ; Oranjemund, top of Hellskloof , 2816 BD, 15 September 1977, Bayer 1023 ( NBG!) .

Remarks:— Oxalis magnifolia displays considerable leaf size variation, with some collections presenting amongst the largest leaves ever recorded among South African members of Oxalis . The leaflets are most often prostrate, waxy and glaucous, and often purple below. Unlike most Oxalis species, the peduncles are always much thicker than the petioles. The plants have a tendency to fall apart in the dried state. The type specimen of O. magnifolia is generally more callose than all other specimens studied, but we decided to retain it as type for consistency in typification with specimens of M.B. Bayer. Eastern populations tend to have smaller, more erect leaves (corresponding to the manuscript name O. glauca of M.B. Bayer), but we have found no morphological division that would support varietal status. We have not observed this species in its type locality (Steenbokberg), but this locality is south of the Richtersveld and this character may be typical of southern populations. An unusual variety with erect, reduplicate leaves was observed in the field. It remained distinct in cultivation, and is thus described below.

Figures

FIGURE 4. Oxalis magnifolia. A.Typical habitat in the Richtersveld National Park and Conservancy. B. Oxalis magnifolia var.magnifolia in full flower. C. Oxalis magnifolia var. magnifolia leaf. D. Smaller growth form of O. magnifolia var. magnifolia from the southern parts of the Richtersveld (Steinkopf area; Oberlander, Dreyer & Roets 2015/07-01). E. Oxalis magnifolia var. reduplicata flowering in the field. F.O. magnifolia var. reduplicata leaf. G. Bulb of O. magnifolia var. magnifolia. Scale bars = 10 mm. Photographs by F. Roets.