January 25, 1906 J 



NA TURE 



295 



of granitic rock with quite a sparse covering of calcareous 

 matter, or to be a filling in with the remains of some of 

 the reef organisms between masses or islets of granite 

 and the land. The reef in the large bay to the north of 



use I. <f 



C335, Feiicite/^ «J? ^ 



-Islands of the Seychelles Gr 



Praslin, extending along the coast for ih miles between 

 two points, is a good instance of this, one islet and three 

 series of granite masses lying at almost equal intervals 

 imbedded in its seaward edge. The boat passages through 

 the reefs are in most situ- 

 ations mere outfalls for the 

 tide, and show no connec- 

 tion with the fresh-water 

 streams off the land. Finally, 

 it is interesting to note that 

 the actual surfaces of the 

 flats are covered with a far 

 greater variety of large sea- 

 weeds than we found in any 

 of the purely coral groups 

 we visited in the 5cdi.ii/, 



The land animals neces- 

 sarily to a large extent de- 

 pend on the plants, and I 

 considered it inadvisable to 

 attempt their complete col- 

 lection in the limited time 

 at our disposal save in the 

 indigenous jungle. Small 

 mangrove swamps occur on 

 the sea-shore, but behind 

 these the land has been 

 almost completely cleared 

 for the cultivation of cotton, 

 coffee, cassava, cocoa, and 

 vanilla to a height of 1500 

 feet. Below this there are 

 only a few isolated endemic 

 trees, and above there are 

 in patches in the jungles 

 large numbers of oranges, 



limes, citrons, and cinnamons, with an undergrowth of 

 the Mauritius raspberry, all introduced plants. Indeed, 

 there are, except in Silhouette, only a few summits and 

 precipitous slopes which have not been at one time or 



NO. 1891, VOL 73] 



another completely planted, and it seems possible that 

 even these may 1"- destroyed within a few years for the 

 cultivation of various rubbers. Such jungles as now remain 

 consist mainly of palms (Roscheria, Stevensonia, NVphro- 

 sperma, Versi haffeltia), various screw 

 pines (Pandanus), Dracaena, and the 

 bois rouge (Wormia), with bare 

 ground beneath covered by their 

 strong leaves, clumps only of Curcu- 

 ligo. Open spots, however, have a 

 dense undergrowth of ferns, Lyto- 

 podia, Selaginellae, Psilota, and 

 mosses, which also cover the lower 

 parts of the trees. In effect, it is a 

 typical, tropical, moist forest under- 

 growth, noticeable mainly for tin- 

 comparative absence of climbing 

 plants and herbaceous dicotyledons, 

 and for the fact that nearlv all the 

 larger trees are peculiar Seychelles- 

 species, and often genera. Most of 

 the giant trees (Maba, Stadtmannia, 

 Afzelia, Campnosperma, &c), have been 

 singled out and cut, but bare stems ol 

 capucin (Northea seychellarum) stand 

 up everywhere above the foliage. The 

 destruction of the latter, which prob- 

 ablv will shortly be complete, we dis- 

 covered to be due to a green beetle, 

 which deposits its eggs singly in the 

 new leaf-buds, the resulting maggot 

 consuming all their softer parts. 



The most interesting feature in the 

 botanv was the sharp distinction of 

 the cotyledonous plants into three 

 classes, the calciphilous, the silici- 

 philous, and the indifferents, the latter 

 forming a smaller percentage of the 

 in-s in fathoms. whole than either of the other two. 



The calciphilous species are practically 

 the same as we found on all the coral 

 islands we visited, and are scarcely more numerous. This 

 group of plants was, I consider, ocean-carried, the Sey- 

 , helles l«-ing in respect to it as oceanic as any island of 

 the Chagos Archipelago. Moreover, of the other trees 



Frigate 

 Recif <{U40o) 



(158) s? 



J Miles 



-Fringing R 



many seemed to possess seeds, which could have been 

 brought by currents, &c, to the islands. The finest in- 

 dividual species of tree was the coco-de-mer, or double 

 coconut (Lodoicea seychellarum), which is peculiar to 



