INTRODUCTORY CHAPTER. 



Ixi 



Africa, but are altogether absent from Asia. Of these Anthericum is a genus of 

 wide distribution throughout Europe, America, and Africa; and it is a significant 

 fact that only one of the others occurs off the African continent. This one is 

 Aloe, which has its headquarters in south Africa, and reaches the Atlantic and 

 Mascarene Islands and the Mediterranean region. Thus eleven of the genera 

 are peculiarly continental African, and their geographical areas are so remark- 

 able that I add here a table to exhibit them : — 



Table showing distribution of eleven genera with endemic species in 

 the phanerogamic flora of socotra which are confined to the 

 African continent. 





< 

 O 



"3 



'3. ?, 



93 

 W 



S3 



u 



03 

 S3 



•a 



.5 



< 



< 



C3* 



a 



2 



'a 



b. 



B 

 O 

 O 



4 





Eureiandra, 



Dirichletia, 



Euclea, 



Ectadiopsis, 



Camptoloma, . 



Graderia, 



Lasiocarys, 



Cephalocroton, 



Babiana, 



Hsemanthus, . 



Rhynchelytrum, 







X 

 X 

 X 

 X 

 X 



X 

 X 



X 

 X 



X 



X 



X 

 X 



X 

 X 



X 

 X 



X 

 X 



Tritypic. Third species Socotran. 

 Seven species. Three endemic in Socotra. 



Six species. Two, perhaps three, endemic in Socotra. 

 Ditypic. Second species endemic in Socotra. 

 Tritypic. Third species endemic in Socotra. 

 Five species. Two endemic in Socotra. 

 Tritypic. Third species endemic in Socotra. 



Tritypic. Third species endemic in Socotra. 



The affinities with the south African flora, and with that of the higher lands 

 upon the west, east, and north-east of Africa, is so clearly brought out in this 

 table that no words are needed to emphasise the relationship. But I may just 

 note this interesting fact, that three of the genera are Monocotyledones. There 

 are only fifteen Socotran genera of Monocotyledones with endemic species ; of 

 these one is itself endemic, and five are African, but absent from Asia. 



Of no less interest than the African genera which are not Asian, are the six 

 Asian genera which are not African. Prenanthes is a large genus with a wide 

 temperate distribution, chiefly American, but extending to the Canary Islands, 

 Europe, and northern India, without representation on the African con- 

 tinent. Elwocarpus and P or ana are genera of considerable size and area in 

 the old-world tropics, both reaching Australia, and occurring in India and 

 Madagascar, the former also in the Mascarene Islands, and their absence 

 from Africa, in view of their last-mentioned localities, is striking. The pre- 

 sence of the ditypic Priotropis, of which the only other species inhabits 

 tropical districts of the eastern Himalayas, from Khasia to Sikkim, is an 

 Indian relationship of great importance. Lastly, Punica, of which the cul- 

 tivated P. Granatum is the only other known species, is supposed to be native 

 of the region including Persia, Kurdistan, Affghanistan, and Beloochistan ; 

 and Campylanthus, with four non-Socotran species, has one species at Aden, 



