10 FLORA OF ST. CROIK AND THE VIRGIN ISLANDS. 



Interspersed between these evergreens are seen various species of 

 arboreous plants with deciduous leaves, the number of which, however, 

 seldom is large enough to seriously change the general aspect of the 

 forest as being uniformly green all the year round. The time for shed- 

 ding their foliage in these forms is generally from January to Ai)ril, 

 most of them, as stated before, flowering precociously at this time, as 

 the moisture in the ground is not sufficient to allow them to retain their 

 foliage together with the producing of the flowers. It appears evident 

 tliat this is the reason for the shedding of the leaves, from the fact ob- 

 served by me in several species (such as Piscidia Erythrina and others), 

 that individuals which, from being too young or for some other reason, 

 do not flower, do not shed their foliage, but evidently find moisture 

 enough in the soil to resist the drought, not having to spend their 

 resources on the production of flowers and fruits, as others of their kind. 



The most x^rominent among the trees and shrubs with a deciduous 

 foliage are Spondias lutca, Sclimidelia occidentalism the enormous EHo- 

 dendron avfnichiosum, Hura crepitans, Caseariaramiflora, Sabinea florida, 

 and several others, which all more than the evergreens contribute their 

 share to the forming of a layer of leaf-mould under the taller forms. Yet 

 this layer is but scanty in most places, and from the want of it, as well 

 as from the dense shade jiroduced by the evergreen trees and shrubs, 

 the minor forms covering the groimd are comjjaratively scarce, and 

 chiefly confined to some Piperaceae, Acanthacese, and Graminese, as 

 well as a few ferns and mosses, among which Jlemionitis palmata, Pteris 

 pedata, and AspJeniuyn pusillum are the most common. 



A somewhat richer variety is presented by the numerous epiphytes 

 that cover the branches and stems of trees and shrubs, notwithstanding 

 that the bark of the latter, from the uniform tem]3erature, is, as a rule, 

 exceedingly smooth, and but rarely covered with lichens or mosses. Of 

 real i)arasites only a few are met with, especially Loranthus emarginatus, 

 whilst the non parasitical epiphytes are numerously represented by 

 Bromeliacece (principally the genus Tillandsia), Aroidea? (among them 

 the large-leaved PMlodendron giganteum), and Orchidacefe (chiefly Epi- 

 dendrums and Oncidiums), as well as some ferns. Of these latter families, 

 several species are found only on the highest ridges of the islands, 

 at an elevation of over 1300', there forming a formation peculiar to 

 these regions, comprising, among others, some terrestrial Orchids, such 

 as Hahenaria maculosa and alata, as well as some Aroidese, BromeUacese, 

 and ferns, among which the beautiful Cyathea arhorea deserves special 

 mention. 



