ii BOTANY OF SOCOTRA. 



xlvi 



! its designation implies, may be regarded as representing the primitive stock 



a ^ 6£ the pomegranate. The gynaeceum consists of but a single whorl of carpels, 



k' the placenta being spread out over the floor of each carpel, and there is never 



any sign of the second whorl of the cultivated form. 



Geraniaceae, with three species on the island, presents us with an endemic 



genus, Dirachma, which is, as regards its affinities, somewhat puzzling. Tiliaceae, 



Sterculiaceae, and Samydaceae may all in some degree claim the genus, but the 



preponderance of characters seems to place it in Geraniaceae, and there its 



relationships appear to be with monotypic south American genera, and thus 



it is one of the forms from the Indian Ocean whose affinities are antipodean. 



Apocynaceae is another three-membered order which has features of interest. 



One species is endemic, and constitutes a new genus Socotora, which in all its 



characters shows strong individuality, and is a very exceptional one. Another 



species is Adenium multijlorum, one of the gouty plants from the island, and 



only known elsewhere in Mozambique. Santalaceae, which also has three species, 



may be mentioned here that I may point out the curious dimorphism in the 



staminate flowers of the endemic Osyris pendula, and that the Thesidium is 



probably an endemic species, but is indeterminable from our specimens. 



Of nine orders which have two species in Socotra I will mention here 



Menispermaceae, noteworthy on account of the cladodiferous and spinose 



Cocculus Balfourii; Illecebraceae, represented by two species, each the type of 



an endemic genus, — Haya allied to Illecebrum, and Lochia having affinity with 



Gymnocarpos ; Irideae, which has an endemic species of the south African genus 



Bdbiana, now in cultivation at Kew, and an endemic variety of Romulea 



purpurascens, the bulbs of which are said to be eaten in Socotra, and which it is 



recorded Wellsted brought from Socotra; and Amaryllideae, with a handsome 



and fragrant endemic Crinum, now in cultivation in Britain, and an endemic 



Hcemanthus, of which the very large leaves only are known. It will be observed 



that Illecebraceae and Amaryllideae are represented by endemic species alone, 



and that Irideae has one endemic species, and an endemic variety of its second 



representative. 



Twenty families have only one representative in Socotra, and in the case of 



nine the species is endemic, and one constitutes an endemic genus. Amongst 



these, Rutaceae is remarkable, for its representative Thamnosma socotr ana belongs 



to a genus which has only two other species, both of which are north American. 



Begoniaceae deserves mention on account of the beauty of its member Begonia 



socotrana, a plant now in cultivation in Europe, and peculiar in its bulbiferous 



character and orbicular leaves. Valerianella affinis of the Valerianaceae is an 



endemic annual. The selagineous plant constitutes an endemic genus Cock- 



burnia, nearly allied to Globularia, a genus of the Mediterranean region, central 



Europe, and the Canary Islands. Lasiosiphon socotranus, the endemic and only 



