b FLORA OF ST. CROIX AND TIIK VIRGIN ISLANDS. 



evaporated n^am l>y the action of the sun and the trade-wind combined. 

 It is not till ^lay, when tlic increased quantity <»f rain is suificient to 

 penetrate the parched soil, tliat its influence and eflect upon vegetation 

 makes itself felt by renewed life and activity in all the various branches 

 of the vegetable Idngdoin in general. 



Looking at the vegetation of St. Croix and tlie Virgin Islands in its 

 generality, and without entering into details, we may consider it to be 

 identical, as a Avhole, showing the same main features, and naturally 

 divided into four distinct Ibrniations, as in most other AVest India 

 Islands, viz. the littoral, the shrubby, the sylvan, and the region of 

 cultivation, connected, of com'se, here and there by intermediate forma- 

 tions, but on the whole virtually distinct from different biological con- 

 ditions. 



Beginning with the littoral llora, we liiid along the coast in shallow 

 water a multitude of Algie, among which are found some marine Pliane- 

 rogaina^, especially the common T}iaht,s,sia tcfitiiilinnm and Cymodocca 

 mauatonun, and in less quantity the beautiful little Halophila Baillonii, 

 a recently discovered Potamea, with oval delicate leaves, and growing 

 gregariously on the bottom of the sea in coarse gravel. The vegetation 

 of tropical seashores is of a very uniform character all over the world, 

 the physical conditions being similar on them all, and the migration 

 fi-om one shore to another being exceedingly facilitated l)y the sea as 

 well as by birds, storms, and the action and intercourse of the iuliab- 

 itants. Thus, the same species of littoral plants are found on nearly all 

 the West India islands, many of them also inhabitants of far distant 

 shores on the African and Asiatic continents, — belonging to the cosmo- 

 politan and transoceanic si)ecies, a list of which was first prepared by 

 Eobert Brown, and afterwards augmented by A. DeCandolle, and wliicli 

 seem to jiossess an extraordinary faculty for migration. According to 

 the ditferent character of the coast, as sandy, rocky, or swampy, the 

 vegetation on it also assumes a diflerent aspect. 



On the s;in(l> sjiore, which is <'oinp(tsed of a liiif white graxcl, con- 

 sisting ])rincipally of innumerable, i)ieces of broken shells and corals, 

 and thus forming a thick layer of carbonate of lime, we see a luxurious 

 llora of trees, shnd)s, and minor ])lants, which all, on accoinit of the 

 undergroiMKl water collecting from the hills above, generally ha\'e a 

 green api»earance all the year round, even Mhen the hills of the interior 

 present a withered asi>ect from want of rain. Among the trees j^'ow- 

 jug here the most prcMninent are the Jlippomanc Maiiciiiclla, the Cocco- 



