RUBIACE/E OF CENTRAL AMERICA. 51 
cumulation of materials than that which is at present at the disposal 
of botanists, and a more critical comparison than has hitherto been in- 
stituted between the Rubiacee of different parts of tropical America, 
may show that many species have a larger distribution. Thus, Hooker 
has proved, that all the American forms of the genus Drimys (JFinteri, 
chilensis, granatensis and mexicana) are merely forms of one species, 
which therefore has as wide an extension as Gentiana prostrata and 
Trisetum subspicatum, which likewise occur throughout the Andes chaiu*. 
Bentham is of opinion, further, that all American species of Chiococcat 
must be considered as varieties only of C. racemosa, Jacq., which has 
accordingly a very wide extension. But, although it will also be gradu- 
ally found, that a greater number of species are common to different 
countries, than was formerly supposed; yet, on the other hand, new 
characteristic species will be constantly discovered, and thus the pro- 
portion of species, peculiar to different floras, will remain the same. 
Although the Rubiacee essentially preserve their character through- 
out tropical America, analogous species of the same genera occurring 
mostly everywhere; the large natural floras are distinguished partly bya ` 
certain number of peculiar genera, and partly by certain genera com- . 
prising a maximum of species, and lastly by certain species predomi- 
nating in their number of individuals. I will confine myself in this 
place to point out briefly some of the chief differences which in these 
respects characterize the different floras, by way of comparison with 
that of Central America. 
Tn the Antilles the genus Psychotria greatly SM in regard 
to the number of species (about 50). The same is the case with Zzo- 
stemma, of which E. caribeum is very common and prevalent on account 
of its number of individuals; which applies also to many Spermacocee 
(S. tenuior). Peculiar genera are: Lrnodea, Hoffmannia, Stevensia, Isi- 
dorea, Tertrea, Bignolia, Strumpfia, Stenostomum, Scolosanthus, Portlan- 
dia, and Erithalis. 
In Mexico the genera Galium, Borreria, and Bie ire the 
greatest amount of species. Peculiar are: Sommera, Margaris, Deppea, 
and Hezasepalum. 
In Guiana the Cophaelidee have their proper home; they have only 
* The Botany of the Antarctic Voyage. m 
+ Nandy; C dosefola and. npo a, Mart. ; casino Mito. 
minea, Mart. et Galeot., phenostemon, ese Seri and nitida, Benth. pi 
i - 
MISSÓURÍ. 
