lxx BOTANY OF SOCOTRA. 



1. The flora is an insular one, having 



a. Relatively large proportion of orders to genera, and of genera to 



species. 



b. Relatively large proportion of endemic species, and of endemic 



genera, and with a considerable amount of endemic variation. 



c. Small proportion of endemic annuals. 



In support of this statement the tables on pages xxxvi, xl, and xlix, may 

 be referred to. 



2. It is that of a continental island, by which is meant that its features are 

 evidently most nearly related to those of the adjacent continents, with which- 

 the island has undoubtedly been connected. 



The tables on pages xlix, lvi, lxiii, lxvi, and lxvii, bear out this statement. 



3. It has features of great antiquity. 



For evidence of this statement we depend not only upon the character of 

 the flora as a whole, but also upon the peculiar physiognomy of many endemic 

 forms, and their isolation in the groups to which they belong. Cocculus 

 Balfourii, Nirarathamnos socotrana, Dracaena Cinnabari, Dendrosicyos socotrana, 

 Dorstenia gigas, and the like are all individual forms which betoken a remote 

 ancestry. 



4. It contains three conspicuous types of vegetation. 



a. One characteristic of a dry desert-region, in which, too, tropical, 



sub-tropical, and even sub-temperate forms mingle. 



b. One with a general tropical nicies. 



c. One having the imprint of that in a cooler and more temperate 



climate. 



On page xxxiv I have pointed out the prevalence on the plains of many 

 plants having the aspect belonging to a, and on pagexxxv I have noted the pre- 

 sence of some forms which answer the description of those included in b and c. 



5. There is a large admixture of introduced plants, a considerable pro- 

 portion of which are now quite naturalised. Many of them are annuals. 



This is a feature that the tables on pages lxii and lxiii specially illustrate, 

 and it is one which was to be expected in an island with so long a history of 

 occupation by man. 



6. Its affinities are essentially tropical African and Asian, being most pro- 

 nounced with the flora of the regions immediately adjoining, i.e., with north- 

 east Africa and south-west Asia ; but the African element predominates. 



(A) In the African element we find 



a. Forms which belong to those types which people the plain-regions 

 of north-east and tropical Africa, extending to north Africa 



