Ceropegia sect. Chamaesiphon, H. Huber, 1957

Bruyns, Peter V., Klak, Cornelia & Hanáček, Pavel, 2018, An account of Ceropegia sect. Chamaesiphon (Apocynaceae) in Moçambique with new records and two new species, Phytotaxa 364 (2), pp. 111-135 : 113

Key to the species of Ceropegia sect. Chamaesiphon in Moçambique

1. Plant 40–70 cm tall with slender erect glabrous stems and filiform glabrous leaves 30–80 × ± 1 mm, bearing flowers in slender racemes 60–90 mm long alongside upper nodes, pedicels and sepals glabrous ................................................................. C. filifolia

1. Plant 5–30 cm tall, stems often branching close to ground and spreading (more rarely erect), puberulous to finely pubescent with ovate to linear (glabrous) puberulous to finely pubescent leaves (1)2–25(50) mm broad, flowers solitary or in sessile clusters alongside nodes or in dense terminal umbels, pedicels and sepals puberulous to pubescent ........................................................... 2.

2. Stems 3–6 mm thick, leaves 5–10 × 3–5 cm, inflorescence a dense terminal umbel of 20–45 flowers opening ± simultaneously with lobes broader than long ................................................................................................................................................ C. buchananii

2. Stems 1–2(3) mm thick, leaves <4 × 2 cm, flowers in groups of 1–11 next to nodes, lobes usually at least 1.5 times longer than broad.................................................................................................................................................................................................. 3.

3. Corolla 35–70 mm diam., flowers in groups of 8–11 alongside nodes ............................................................................................. 4.

3. Corolla <35 mm diam., flowers solitary or up to 5 alongside nodes................................................................................................ 5.

4. Stem 5–10 cm tall, branched near base with branches spreading close to ground, leaves ± 1 mm broad, glabrous, flowers 35–40 mm diam., outer corona with hairs inside ..................................................................................................................... C. cyperifolia

4. Stem unbranched and 10–30 cm tall, leaves ± 10 mm broad, finely pubescent, corolla 50–70 mm diam., outer corona glaous........ ....................................................................................................................................................................................... C. gracilidens

5. Pedicel ≥ 6 mm long.......................................................................................................................................................................... 6.

5. Pedicel 1–4 mm long......................................................................................................................................................................... 8.

6. Corolla-lobes more than four times as long as broad at base, slender and linear................................................................. C. nutans

6. Corolla-lobes 1–3 times as long as broad at base, oblanceolate to deltate........................................................................................ 7.

7. Corolla-lobes longitudinally slightly folded but without rugulose inner surface and not distinctly thickened apically, inside covered with crinkled white hairs especially towards tips, corona glabrous ................................................................................ C. albipilosa

7. Corolla-lobes rugulose inside (often purple-black) and often with distinctly thickened apical area, ± glabrous, outer corona with short hairs inside near bases of lobes .......................................................................................................................... C. plocamoides

8. Corolla-lobes remaining joined at tips and corolla cage-like at anthesis, outer corona of five discrete lobes each deeply bifid into slender erect slightly spreading teeth, alternating with inner lobes which ± cover anthers ............................................. C. circinata

8. Corolla campanulate to rotate with lobes spreading, outer coronal lobes fused into cup-like structure with short rounded or truncate inner lobes just touching backs of anthers and fused to inside of outer coronal cup ........................................................................ 9.

9. Corolla-lobes linear, inside maroon-black with maroon-black hairs to 5 mm long in upper half, outer coronal lobes with U-shaped gaps opposite guide-rails, glabrous inside............................................................................................................................ C. tavalla

9. Corolla-lobes deltate, inside yellow-green to brown, glabrous or finely pubescent towards margins, outer coronal lobes with narrow slit opposite guide-rails or entire, with fine hairs inside .......................................................................................................... 10.

10. Plant spreading and usually with several spreading branches, corolla-lobes glabrous inside, outer corona entire (without notches opposite guide-rails), uniformly pale green....................................................................................................................... C. cupulata

10. Plant erect with single stem, corolla-lobes finely pubescent inside towards margins, outer coronal cup deeply (but finely) notched opposite guide-rails, usually with maroon-black or purple-brown rim.............................................................................. C. simplex