lxviii BOTANY OF SOCOTRA. 



and Arabia ; and twenty-three plants belonging to the following genera, of 

 which our material is not adequate for a more precise determination : — 



Farsetia, sp. 



Hibiscus, sp. 

 IJoswellia, sp. 2. 

 Balsarnodendron, sp. 2. 

 Allophylus, sp. 



Eiythiina, sp. 



Entada, sp. 

 Acacia, sp. 

 Euclea, sp. 2. 

 Ectadiopsis, sp. 

 Sareostemma, sp. 

 Boucerosia, sp. 2. 



Ehretia, sp. 

 Plectrantlms, sp. 

 Aristolocliia, sp. 

 Loranthus, sp. 

 Thesidium, sp. 

 Ficus, sp. 



It is probable that several of these imperfectly determined plants are endemic. 



We have 253 species of Cryptogams from the island, Lichens forming a little 

 more than half of the number. The distribution of the species amongst the 

 several groups is shown in the table on page xxxvi. 



If we have to consider the statistical analysis of the phanerogamic flora as 

 only approximative, the same holds good, with increased force, for the Crypto- 

 gams. Less is known of the cryptogamic than of the phanerogamic flora of the 

 adjacent mainlands, and the limitations of many genera and species in the 

 Thallophyta especially, are admittedly so loosely defined at the present time 

 that these afford an unsatisfactory basis for comparison; and then our collection 

 of Cellular Cryptogams is even more fragmentary than that of Phanerogams, 

 Lichens being the only group of which Ave have at all a representative gathering. 

 I can only then write a brief account of the general features of the cryptogamic 

 flora. 



The position of Socotra prepares us for just such a cryptogamic flora as we 

 know from the island. The large expanses of limestone, and the dry soil and 

 climate of the greater part of the island, are not favourable to a development of 

 luxuriant Ferns or delicate Muscinese, and the only group of Cryptogams to 

 which the conditions are at all suited is that of Lichens. The few Ferns that do 

 grow on the island are mostly those which affect dry localities, and are found, 

 like Cheilanthes farinosa or Onychium melanolepis, hidden under boulders, or, 

 like Actinopteris dichotoma, occupying cavities in rocks on the hill-sides. 

 Ceratopteris ihalictroides banks the streams on Hadibu plain ; whilst some, like 

 Pellcea concolor, occur at a high altitude on the Haghier hills, where the 

 climate is moister and more temperate. The Mosses and Liverworts are 

 chiefly found upon the central granitic hills, high above the dry limestone- 

 plains, though some, like Weisia socotrana and Fimbriaria pusilla, grow in 

 the lower arid districts. Lichens grow in great numbers all over the island, 

 and, as we know them, far outnumber all other Cryptogams. There is a marked 

 absence of foliaceous and fruticose forms, by far the larger number being 

 crustaceous. They colour the rocks in all localities, the prevailing tone being 

 greyish-white, derived from species of Roccella, Pertusaria, and Parmelia ; the 

 steins of many of the trees have also coatings of Opegrapha, Gi'aphina, and 

 species of other genera. Other Fungi are not abundant, although doubtless a 



