454 -^I- ASCLEPIADACEAE 



Sepals small, usually with glands. Leaves herbaceous. Flowers small or 

 of moderate size. — Species 17. Tropical and South Africa. Some 

 species yield rubber or serve as vegetables. (Including Dregea E. Mey. 

 and Pterygocarpus Höchst.) Marsdenia R. Br. 



93. (78.) Stem cactus-like, thick and fleshy, with 4 or more angles or rows of 



tubercles, usually low. Leaves more or less rudimentary or wanting. 

 Flowers solitary or in fascicles, fleshy. Sepals pointed, with solitary 

 glands. Corolla-segments very rarely coherent at the tip. Stigmatic 



head flat or ending in a small boss 94 



Stem herbaceous or woody, rarely {Ceropegia) fleshy, but then leafy or 

 obscurely 3-angled and corolla-segments cohering at the tip, at least 

 when young 106 



94. Branches divided by longitudinal and transverse furrows into several- 



ranked areas, not spiny nor bristly. Corolla rotate or campanulate, 

 cleft to the middle. Corona-lobes 5 or 10, united at the base. — 



Species 7. East Africa Echidnopsis Hook. fil. 



Branches angled or tubercled, but not divided into areas, usually spiny 

 or bristly 95 



95. Branches with more than 6 angles or rows of tubercles, rarely with 6 ; 



in this case with 3-parted spines 96 



Branches with 4, more rarely with 5 or 6 angles or rows of tubercles. Spines 

 or other appendages of the tubercles simple 98 



96. Spines 3-parted. Flowers solitary or in pairs, large. Corolla tube- or 



funnel-shaped, shortly lobed. Corona double, the outer divided into la 

 filiform segments terminating in knobs. — Species 2. South Africa and 

 southern West Africa. {Tavaresia Welw.) . . Decabelone Decne. 

 Spines simple or absent. Corolla saucer- or cup-shaped. Outer corona 

 of 5 two-lobed or two-parted pointed lobes or indistinct 97 



97. Tubercles of the stem united into continuous angles, spiny. Flowers large. 



Corolla slightly lobed. — Species 10. South and Central Africa. Hoodia Sweet 



Tubercles of the stem not confluent. Flowers rather small. Corolla 



lobed to about halfway. — Species 12. South Africa and southern 



Central Africa Trichocaulon N. E. Brown 



98. Corolla-segments cohering at the tip. Corona double. — Species 5. South 



Africa. Used as vegetables Pectinaria Haw. 



Corolla-segments free at the tip 99 



99. Corona simple, of 5 lobes 100 



Corona double or triple loi 



100. Sepals large. Corolla campanulate, divided half-way down, hairy, inside 



red mottled with yellow. Corona-lobes thick, without a dorsal crest : — 

 Species i. South Africa to Damaraland. {Huerniopsis N. E. Brown). 



Heurniopsis N. E. Brown 



Sepals small. Corolla rotate or campanulate, divided to beyond the 



middle. Corona-lobes with a dorsal tranverse crest at the base. — 



Species 10. South Africa Piaranthus R. Br. 



