Ceropegia cryptobarbata Heiduk, 2023

Heiduk, Annemarie, 2023, Ceropegia cryptobarbata sect. Chamaesiphon (Apocynaceae-Asclepiadoideae), a novel tuberous species from the Drakensberg foothills in South Africa, Phytotaxa 613 (2), pp. 162-170 : 163-166

Ceropegia cryptobarbata Heiduk , sp. nov. ( Figs 1 & 2 ).

Type: — SOUTH AFRICA. KwaZulu-Natal: Underberg (2929), Kamberg (— BC), ca. 2020 m, 17 January 2020, D. G. A . Styles & A . Heiduk 5774 (holotype NU! [ NU0094286 ]; isotype NU! [ NU0094574 ]) .

Diagnosis: — Ceropegia cryptobarbata is vegetatively and floristically most similar to C. oiantha . It differs in having shorter leaves (23– 34 mm vs. 40–50 mm [– 60 mm, Dyer 1980] in C. oiantha ), with obtuse tips (vs. acute in C. oiantha ), much smaller bracts (3 mm vs. 5–8 mm in C. oiantha ), longer petioles (±4.5–7.0 mm vs. absent in C. oiantha ), more slender and shorter sepals (3 mm vs.> 5 mm in C. oiantha ) which are narrowly triangular (vs. broadly subulate to ensiform in C. oiantha ), and shorter (18 mm vs. 20–28 mm in C. oiantha ), cupuliform-campanulate (vs. ovoid-urceolate in C. oiantha ) flowers with a fluted and scabrid outer surface (vs. glabrous in C. oiantha ). The corolla tube of C. cryptobarbata is not constricted at the mouth (vs. constricted in C. oiantha ) and the corolla lobes are longer (6 mm vs. 3–3.5 mm in C. oiantha ). The corona is densely barbate with trichomes (vs. glabrous, sometimes tufts of white hairs on outer lobes in C. oiantha ). The follicles are slenderly fusiform (vs. thickly fusiform in C. oiantha ), and distinctly longitudinally furrowed (vs. smooth in C. oiantha ).

Description: —Plants perennial, dwarf herbs with a tuber. Tuber flattened-elliptic, 65–87 × 51–53 mm, somewhat centrally depressed. Stems single or two (rarely 3), annual, unbranched, 38–77 mm long, 1.5–2.5 mm in diam., sub-erect spreading, glabrous, green with purple markings. Leaves broadly ovate-elliptic to oblanceolate, 23–34 × 14–17 mm, tip obtuse to rounded, green with faint purple margin, somewhat scabrid above and below, tapering into an adaxially channeled petiole 4.5–7.0 mm long. Inflorescences uniflorous, with narrowly-triangular ± 3 mm long bract. Pedicel curved, 7–10 mm long, ± 1.5 mm in diam., green with purple tinge. Calyx lobes narrowly-triangular, ± 3 mm long, ± 1 mm broad at base, green. Corolla deeply cupuliform-campanulate, ± 18 mm in total length, outside light creamishgreen, fluted, scabrid. Corolla tube ± 13 mm long, ± 13 mm wide at mouth, inner surface velvety, with circularly arranged dark purplish-red stripes, with rows of stiff, narrowly fusiform, ±2.5–3.0 mm long, purple trichomes along along the corolla fusion-lines in distal half of the tube. Corolla lobes triangular, ± 6 mm long, ± 6.5 mm broad at base, ciliate, distally acuminate often with tips incurved, with longitudinal dark purplish-red markings and short purple trichomes. Gynostegial corona sessile, of staminal and interstaminal parts, 3.5 mm high, ± 5.5 mm in diam., yellowish at base merging into dark brown-purple towards lobes, densely hirsute to barbate with dark purple trichomes up to 1.2 mm long; outer corona lobes forming five pockets with V-shaped margin, slightly reflexed, bearded with purple trichomes; inner corona lobes adpressed to back of stamens and rising along them, with tips of lobes descending onto the style-head. Pollinarium with broadly ovoid to oblanceolate pollinia; pollinium ±430 × 340 µm, brown merging yellowish towards insertion crest, corpusculum sagittate to obclavate, ±390 × 210 µm, translator arm ±120 µm long. Follicles with two mericarps, erect, narrowly fusiform, longitudinally furrowed, ±86 × 7 mm, glabrous, green. Seeds not seen.

Figures

FIGURE 1. Floral features of Ceropegia cryptobarbata (A,C,E,G) and C. oiantha (B,D,F,H) in comparison. A, B, Floral bracts. C, D, Corolla in lateral view. E, F, Gynostegium in lateral view. G, H, Gynostegium in top view. Scale bars: 1 mm (A), 6 mm (B), 5 mm (C,D), 1 mm (E–H). Photographs: Annemarie Heiduk.

FIGURE 2. Ceropegia cryptobarbata from the Drakensberg foothills in KwaZulu-Natal, SouthAfrica. A, Longitudinal section of a flower revealing the barbate gynostegium, the inner corolla colouration and the trichomes. B, Plant with well-developed follicles. C, Pollinarium. D, Habitat at the type locality where plants occur on rocky cliff edges. Scale bars: 3.5 mm (A), 2 cm (B), 200 µm (C). Photographs: Annemarie Heiduk.