Gymnosiphon, Blume, 1827

Cheek, Martin & Traclet, Sébastien, 2020, Gymnosiphon mayottensis Cheek, sp. nov. (Burmanniaceae) a new species from Mayotte, Comoro Islands, Adansonia 42 (8), pp. 179-188 : 181

KEY TO THE SPECIES OF GYMNOSIPHON IN AFRICA, COMORO ISLANDS AND MADAGASCAR

1. Stigmas with filiform extensions exserted from flower at anthesis ................................................................ 2

— Stigmas lacking filiform extensions .............................................................................................................. 5

2. Flowers zygomorphic, inflorescence capitate, Madagascar................................................... G. marieae Cheek — Flowers actinomorphic, inflorescences cymose, Africa and Comoro Islands................................................. 3

3. Perianth tube 2-5 mm long ......................................................................................................................... 4 — Perianth tube 1 mm long ................................................................................. G. constrictus Maas & H.Maas

4. Inflorescence bracts about as long as rhachis internodes, inner tepals absent; stigmas horizontal; tepals changing from white to translucent at anthesis ............................................................... G. mayottensis Cheek , sp. nov.

— Inflorescence bracts <1/4 as long as rhachis internodes, inner tepals present; stigmas pendulous; tepals white at anthesis ............................................................................................................ G. longistylus (Benth.) Hutch .

5. Rootstock with numerous bulbils, ovary ribbed, inner tepals absent, Malawi, NE Zambia, S Tanzania

.................................................................................................................................. G. afro-orientalis Cheek — Rootstocks lacking bulbils, ovary smooth, inner tepals present, Guineo-Congolian Africa or Madagascar....... 6

6. Flowers sessile or subsessile, pedicel if present to 0.5 mm long .................................................................... 7 — Flowers with a distinct pedicel 1 mm long or more ..................................................................................... 8

7. Flowers white, perianth tube> 10 mm long ................................................................... G. bekensis Letouzey — Flowers yellow or white, perianth tube <5 mm long .............................................. G. samoritoureanus Cheek

8. Plants commonly 15-35 cm tall; base of stem completely covered in many tens of brown leaf-scales, E. Africa ...................................................................................................................................... G. usambaricus Engl.

— Plants always <15 cm tall; base of stem sparsely covered, with only 3-4 leaf scales, Madagascar..................... .................................................................................................................................. G. danguyanus H.Perrier