282 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. " 
might easily be extended and with a more thorough study might : 
furnish an interesting question as to the rapidity of multiplication of — 
these plants and as to the means by which they hold their own among 
the more rapidly multiplying plants. As to the question why certain ea 
plants are found on one slope and not on another, the palms as am < 
example may explain. At an altitude of 500 or more meters, palms i 
of various kinds are scattered about among the other forest vegetation. oy 
This occurs, however, only on slopes to the northeast, that is, exposed 
to the northeast trades. The opposite sides at this high altitude 
present an ordinary forest front undotted by a single palm. Moisture, 7 
then, either by its immediate presence or in its relation to the winds i 
very probably is a factor in the distribution of all the plants. r. 
So far as methods of distribution are concerned it may be said that x 
there are very few special adaptations to dispersal. Cenchrus echinatus i 
seems to be the only one adapted for dispersal by means of its prickly ie 
fruit, which adheres to animals. The various members of the Bigno- Ph 
niaceae and of the Asclepiadaceae are suited for wind dispersion * 
are also Gossypium and Bombax. Of course there is no limit to the 
carrying of seeds by birds from one valley to another so that the . 
absence or presence of moisture is probably the most potent factor 
restricting the mountain plants to the mountain and the lowland 
plants to the lowlands. po 
The further question as to the distribution of the plants according 
to season is quite as interesting as the distribution of the plants ™ the s 
various topographical regions. There is a striking difference the 
season and in the dry. In the rainy period the fields are carpeted we 
green and the bushes and trees are heavy with foliage and bright vi fi 
blossoms. In the dry season the fields are almost devoid of stick oo 
leaf and many bushes and trees are to every appearance dead. Z 
the rains come on in July or August, Tribulus terrestris and Kale : 
mia maxima cover the roadsides and plains; Stachytarpheta cocem”” — 
and S. jamaicensis, Spermacoce tenuior, Argemone mexicana, Ashi : 
curassavica, and many others form a rank growth of weeds 10 os : 
coconut groves and cane fields; various shrubs of the hillside, Cappars 
verrucosa, Cassia emarginata, Bauhinia cumanensis, and others are 
out in leaf and in flower; and the climbing shrubs and vines form z : 
luxuriant growth along the ‘“‘rio” beds. In the dry season only @ wal 
of these plants can be found in flower. It is noteworthy that in seve 
