10 FLORA OF ST. CROIX 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 April, 

 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 

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

 served by me in several species (such as Piscidia JErytlirina 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 prominent among the trees and shrubs with a deciduous 

 foliage are Spondias lutea, Schmidelia occidentalism the enormous Erio- 

 dendron anfractuosum. Sura crepitans, Caseariaramiflora, Sabineaflorida, 

 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 produced by the evergreen trees and shrubs, 

 the minor forms covering the ground are comparatively scarce, and 

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

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

 pedata, and Asplenium 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 temperature, is, as a rule, 

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

 real parasites only a few are met with, especially Lorantlius emarginatus, 

 whilst the non -parasitical epiphytes are numerously represented by 

 Bromeliacese (principally the genus Tillandsia), Aroidere (among them 

 the large-leaved PMlodendron giganteum), and Orchidaceae (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, comprisiug, among others, some terrestrial Orchids, such 

 as Habenaria maculosa and alata, as well as some Aroideoe, Bromeliacere, 

 and ferns, among which the beautiful Cyathca arborea deserves special 

 mention. 



