PHANEROGAMS — PROFESSOR BAYLEY BALFOUR. 171 



The stems of, apparently, another Sarcostemma are in our collection, but I 

 have not been able to identify them. 



9. D^EMIA. 



Dccmia, R. Br. in Mem. Wern. Soc. i. 50 ; Benth. et Hook. Gen. PI. ii. 764. 



A small genus of twining species which have a wide range over Africa and 

 tropical and subtropical Asia. 



D. angolensis, Dene, in Ann. Sc. Nat. ser. 2, ix. (1838), 337, and in DC. 

 Prod. viii. 544. 



D. celhiopica, Dene in DC. Prod. viii. 544. 



? Asclepias scandens, Beauv. Flor. O'Ow. et Ben. i. 93, t. 56. 



Nom. Vern. Irrham (Schweinf.). 



Socotra. Common. B.C.S. n. 64, 515. Schweinf. n. 676. 



Distrib. Tropical Africa. 



This is one of the commonest twiners on the plains, and a favourite food of 

 camels. 



The species appears to vary much. The follicles in our Socotran plant are 

 sometimes quite smooth and pubescent, or there may be a slight roughness or 

 murication of surface towards the base. Decaisne describes fruits of D. 

 angolensis as smooth, but Palisot de Beauvois' figure shows a very spiny fruit, 

 and I find in Kew Herbarium specimens from west tropical Africa with the 

 fruit more or less spiny. As regards the flowers, Hooker (Nig. Flor. 454) notes 

 two forms of the species, one, " having the corolla deep purple at the base with 

 greenish-white divisions, is the more northern form found in Senegambia and 

 Guinea, as far as Accra"; "the other, with larger leaves and a pure white 

 corolla, extends from Cape Coast southwards." Our Socotran plant, like the first 

 of these, has a purple corolla. Of continental forms our plant resembles most 

 ^Ethiopian plants, which, however, have persistently scabrid as well as velutino- 

 pubescent stems (in west African plants the stems are sometimes scabrid), and 

 the fruit is almost invariably spiny, the spines being uncinate, whilst in our 

 plants the scabridity is hardly marked on the stems, indeed I only find it on one 

 specimen. It may be possible eventually to differentiate more than one species 

 amongst these forms, but I have not been able to do so at present. 



10. MARSDENIA. 



Marsdenia, R. Br. in Mem. Wern. Soc. i. 28 ; Benth. et Hook. Gen. PI. ii. 772. 



A considerable genus of twining or shrubby plants, widely dispersed over 

 the warmer regions of the globe. One species appears in the Mediterranean 

 region. 



M. robusta, Balf. fil. in Proc. Koy. Soc. Edin. xii. (1883), 79. Tab. LII. 



