Vegetation of Southeast Asia Studies of Forest Types 1963-1965

where the annual precipitation is low and the soil is poor. Many
of the plants, ranging from shrubs to small trees mixed with bamboos
and cacti, are armed with sharp thorns. A similar formation occurs
around Guanica, in southwestern Puerto Rico.
The best analogy, in comparing the vegetation types of Southeast
Asia and Puerto Rico, is the Mangrove forest, which occurs in both
hemispheres. This is a special edaphic association, flourishing in
saline soil in deltas and around the estuaries of rivers. Several
identical genera grow in this forest type in both regions. While
Some stands of Mangrove forest in Thailand and South Vietnam may be
taller than those along the north and south coasts of Puerto Rico,
their physiognomy and life-forms are closely similar. The canopy
is uniform and continuous, with foliage of varying shades of green,
according to species.
Teak (Tectona grandjs) is a characteristic tree of the Mixed Deciduoua
forest of northern Thailand and northwestern Laos. This
commercially valuable timber tree is not native to Vietnam, Cambodia,
or Puerto Rico, although it has been planted successfully in all
these countries.
Numerous species of grasse:;, some forming dominants in the ground
cover, are represented in 3outheast Asia, Puerto Rico and Texas.
.Several species are cosmopolitan. In. addition, certain weeus, such
as KupaLorLum oaoratum, are paritropical, frequent in forest clearir^s
ana along roadways.
Many plants, especially those of economic value as source of food,
fruits, tubers, or planted as ornamental plants, have oeen introduced
from tropical America into Southeast Asia, and likewise ;'rom Asia to
Puerto Rico. A lv iong these may be mentioned: corn, tobacco, cotton,
-assava or manioc (Manihot esculenta), peanuts, ana sucn fruit trees
as Mango (MangU'cra iridica), tamarini (Taraar Indus indiea), papaya
(Jarioa papaya), ponuxrosa (gXtgenia .'.amopsT^and al.T.endra (Tcrirdnalia
catrippa)"; in addition to ma:iogany (o..'ielenia mai:a::oni and ^3. :nacropriylla)',
African ttilip tree (Spatnodea campa:ialata)', and t::e raintree
\kntc;rplobiurn saman) grown along avenues and in parks.
A list of plant families common to Southeast Asia, Puerto Rico
and Texas, and indicative of the similarity of the vegetation of
these widely separtted regions, follows;