149 



THE GENEKA OF STAPELIEM. 



The most recent number (March, 1890) of the ' Icones Planta- 

 rum' is devoted entirely to illustrations and descriptions of the 

 Stapeliece collected by Sir Henry Barkly in South Africa, from the 

 pen (and in some instances from the pencil) of Mr. N. E. Brown. 

 Mr. Brown has for twenty years worked assiduously at this 

 interesting and difficult group of plants, and the present may be 

 regarded as a contribution to the monograph which we hope for 

 from his pen. Besides the descriptions and figures, Mr. Brown 

 gives us a key to the genera, prefaced by an interesting sketch of 

 the growth of our knowledge of the group, and valuable remarks 

 based upon his studies of the plants in cultivation as well as in a 

 dried state. These tend to show that the reduction of genera here 

 made by Mr. Brown will be carried further as our knowledge of the 

 group increases. "In spite of having thus limited the genera to 

 few, rather than increased their numbers," he says, " I am of 

 opinion that some of the genera still retained are more artificial 

 than natural ; for instance, Frerea and Trichocaulon only differ 

 from Caralluma in habit, and Trichocaulon only differs from Hoodia 

 in its corolla, for although some of the species have a different 

 corona, one has a corona undistinguishable from that of Hoodia; 

 possibly it would be more logical and convenient, after all, to do as 

 our predecessors did, and place them all in the genus Stapelia, with 

 the exception of Decabelone, Diplocyatha, Duvalia, Huernia, and 

 Hucrniopsis." Thirteen genera, however, are still retained, and 

 are arranged by Mr. Brown as follows : — 



I. Corona simple, outer corona wanting (very rudimentary in 



Echidnopsis. See also Caralluma hottentotorum). 



1. Stems usually 4-angled, occasionally 5- to 6-angled, short. 

 Corolla distinctly campanulate ; coronal segments stout, with 



the apex produced, erect. 8. Huerniopsis N. E. Br. 

 Corolla rotate, or rarely with a very short tube, not cam- 

 panulate ; coronal segments crested on the back. 12. Pia- 

 ranthus K. Br. 



2. Stems teretely many-angled, tessellate-tuberculate, elongating. 



Corolla small, saucer-shaped ; coronal segments not crested. 

 3. Echidnopsis Hook. f. 



II. Corona double, outer corona present, arising from the staminal 



tube. 



1. Lobes of the corolla cohering at their apex. 4. PECTiNARiAHaw. 



2. Lobes of the corolla not cohering at their apex. 



A. Limb of the corolla nearly entire, 5-cuspidate, the lobes 

 almost obsolete, outer corona cup-shaped, 5-lobed ; stems 

 with numerous tuberculate angles, the tubercles bristle- 

 tipped. 6. Hoodia Sweet. 



