lx BOTANY OF SOCOTRA. 



Lotus, Dichrostachys, Punica, Dirichletia, Pulicaria, Ectadiopsis, Secamone, 

 Blepharis,Barleria,Neuracanthus,Ladosiphon,&Ti& Cephalocroton. In some cases 

 the aberration of the species are of no great extent ; in others the modification 

 of the genus required is so great that it becomes a question whether or not the 

 Socotran plants have sufficient individuality to form a distinct and new genus. 



Fifty-four genera with endemic species have a wide geographical area in both 

 the old and new world. Most of them are conspicuously tropical genera, but 

 some have a considerable range in extra-tropical and temperate regions. 

 Hypericum, Carum, Peucedanum, Valerianella, Teucrium, Habenaria, for instance, 

 are genera with considerable temperate development, and in the tropics found 

 usually in mountainous districts. Rhus has but a small tropical representation. 

 The majority of genera of the category we are now considering are extensive 

 ones, with almost cosmopolitan range within their latitudes, but such ones as 

 Crotalaria, Indigo/era, Tephrosia, Acacia, Kalanchoe, and Tetragonia may be said 

 to attain their maxima in tropical and south Africa, and the section of Senecio 

 which occurs in Socotra is south African. Dorstenia has a very large develop- 

 ment in Africa, but few species are Asian ; and Tetragonia is not known yet 

 from the Orient region of Asia adjacent to Socotra. 



Amongst the twelve genera of old-world distribution, only Brassica and Lotus 

 have considerable range in temperate regions, and the latter especially frequents 

 highlands in the tropics ; Helichrysum has a maximum development in Africa, 

 especially in south Africa, and has few representatives in Asia east of the 

 Orient region, and Launcea extends from the Canary Islands to India. 



The presence of Thamnosma, a genus with only two representatives, natives 

 of southern north America, is one of those features of distribution in this 

 region difficult to explain adequately. 



Several of the twenty-six genera recorded in the table as of restricted area 

 in Africa and Asia are deserving of notice. Several are small genera, with 

 remarkable sporadic distribution. Taverniera is characteristically a genus of 

 south-west Asia, but is also found in Nubia. Psiadia is essentially tropical 

 and subtropical African, extending to Madagascar and the Mascarene Islands, 

 but one species reaches Arabia, and thus it has Asian representation. Euryops 

 is almost entirely south African, one species, however, occurs on Kilima Njaro, 

 and another grows in Nile-land and Arabia. The tritypic Vogelia has one 

 south African and one Arabian and north-west Indian species, the other being 

 Socotran. Anisotes, also tritypic, has one Arabian species and one growing in 

 east tropical Africa. Ecbolium is ditypic, the non -Socotran plant being widely 

 spread in tropical Asia and Africa. Lasiosiphon has a maximum development 

 in south Africa, and also occurs in Madagascar. Secamone is interesting, because 

 of the Madagascar relationship of the Socotran species. 



There arc thirteen genera with endemic Socotran species which occur in 



