AND CENTRAL AMERICA. 85 
The genus is spread both over the Old and New World, belonging 
with few exceptions only to the hot zone. The East Indies and Sunda 
Islands, especially Java, are its head-quarters in the Old World; only 
few species have been found in China and Japan, at Madagascar or the 
Cape. But all these form scarcely one-third of the number already 
known from America; and this preponderance will be augmented by a 
considerable increase of new forms contained in the present memoir. 
The 108 hitherto described American species extend from Brazil to the 
northern tropic, beyond which, as far as is known, none occurs. They 
are much more numerous in South America than in the tropical part of 
North America. Of 81 species of South American Begonias, as many 
as 57 belong to Brazil, forming as it were the centrum of the genus in 
. South America. The other centrum is in North America, in Mexico, 
from whence 14 species have been made known; a number increased 
to 30 by those which I have discovered. 
Generally the species have a very limited geographical extension, 
which no doubt may be accounted for by the nature of their localities ; 
they being found in shady moist places, in the humid rich soil of pri- 
meval forests, in the depths of the Barrancas, and in the clefts of rocks ; 
from all which places that great agency in the dispersion of plants, the 
wind, is excluded. I have only met with one species, B. peltata, Otto 
et Dietrich, growing on the dry and sunny trachyte-rocks in Mexico, 
but this plant, too, has only a limited extension. Hence it may be 
easily explained, why certain Begonias escape the travelling botanist’s 
notice, and necessarily must do so, unless he visits the precise spots 
where they have been found before. 
.. The following are the names of those who have contributed to our 
knowledge of Mexican and Central American Begonias. : 
In Francisco Hernandez’s ‘Nova plantarum regni Mexicani His- 
under the name of To/oncazozo coyollin, 
the others in the work, is so clumsy, 
one has ventured to name the 
toria,’ a Begonia is delineated 
but the woodcut, like most of 
and the description so imperfect, that no é 
plant, which must accordingly be passed over as not to be determined. 
Humboldt and Bonpland found two species m — sspe 
B. gracilis and populifolia, H.B.K. But a far more considerable ad- 
dition is due to the exertions of Schiede and Deppe, who partly for- 
warded dried specimens from Mexico, which were described jean 
tendal and Chamisso, and partly seeds, which were raised in the Berlin 
