FLOEA OF ST. CROIX AND THE VIRGIN ISLANDS. 11 



The part of tlie island iubabitecl aud cultivated by man of course rep- 

 resents tbe least of interest in a phyto-geograpbical sense, as nature here 

 bas been modified and modelled according to the wishes and necessity 

 of society to such an extent as to almost entirely obliterate its original 

 character. As stated already, the principal object of cultivation is the 

 sugar-cane, which, however, is cultivated on a large scale only in the 

 two largest and most level of the islands, Vieques and St. Croix, the 

 others, viz. St. Thomas, St. Jan, Tortola, and Virgin G^rda, having, 

 with a few exceptions, long ago abandoned the cultivation of the cane 

 as unremunerative, the two remaining of the larger islands, Culebra 

 and Anegada, never having been appropriated to that purpose. 



Besides the cane, some Sorghtim vidgare is also cultivated in fields for 

 herbage, the rest of the tilled soil being used for the planting of the 

 common tropical vegetables, generally in small quantities, on patches 

 of soil selected here and there. The commonest of these plants are Yam 

 {Dioscorea alata and altissima), Sweet Potato {Ipomcea Batatas), Okro 

 {Ahelmoschus esculentus), Tanier [Xantliosoma sagittwfolium), Pigeon-pea 

 {Cytisiis Cajan), Tomato, and Pepper (Capsicum), as well as some Cucur- 

 bitacecB, as Pumpkin, Melon, and others. 



Along with these useful plants follow a great number of herbaceous 

 annuals, mostly cosmopolitan weeds, introduced after the settlement of 

 the islands, and dependent on the continuous cultivation of the land, as 

 without the clearing of the soil from shrubs and trees their existence 

 would soon be terminated by the stronger arboreous species, which 

 would deprive them of the necessary light and air. 



Thus, much against his wish, man favours the i)ropagation of innu- 

 merable weeds, which in their short period of vegetation produce seeds 

 enough to secure their continuance on the land notwithstanding the 

 efforts to exterminate them by frequent weeding. Among the com- 

 monest of these forms are some Labiatas {Leonurus sibiricus, Leonotis 

 nepetwfolia, and Leucas martinicensis), Argemone mexicana, Tribulus max- 

 imus, Boerhaavia erecta and panimdata, and especially many grasses 

 and sedges, such as Panicum, Paspalum, Chloris, Digitaria, Cyperus, 

 and others. The most troublesome of these, from an agricultural point 

 of view, is the Bay-grass [Cynodon Bactylon), said to be introduced, but 

 now found everywhere, and, on account of its long creeping rhizoma, 

 inexterminable. 



Similar forms to these are seen growing along roads and ditches, espe- 

 cially some Leguminosse, as Crotalaria, Desmodium, Phaseolus, Clitoria, 



