Tropie Zone: Gulf Region. 661 
In the mountain region forty to sixty miles south of Merida, or beyond 
Ticul, certain new elements are introduced into the vegetation, which impart 
to it a somewhat distinctive character; but, broadly speaking, the flora is still 
that of the northern limestone flats, with its chaparral species as the domin- 
ating feature. At several points on the northern flank of the sierra, there are 
extensive growths of the red gum, the chakah of the Mayas, Bursera gum- 
mifera, destitute of leaves in the dry season, while in the thinner jungle occurs 
Bromelia Pinguin. 
Tropic Forest Formations. “These forest formations cover the area of 
Mexico, which after the removal of the original native vegetation is devoted 
to the cultivation of the sugar cane, banana, coffee, rubber tree, mango, orange, 
papaw, alligator pear, and other tropic economic plants, adapted to a steaming, 
hot, humid climate. In the neighborhood of Papantla in the state of Vera 
Cruz in the heart of the tropic forest is the seat of the vanilla industry of 
Mexico. Tree after tree in this vast forest is covered with the luxuriant vines 
of the vanilla orchid, Vanilla planifolia, indigenous to these wilds. It is with 
this tropic forest, which the writer has seen at three places (Rascon, Cordoba 
and Orizaba), that we are now concerned. 
The forest composed of numerous species is thick, the undergrowth is 
dense and trees and shrubs, according to my observations in the Tamasopo 
Canyon, are bound together by clambering vines to form an almost impenet- 
rable jungle. Each large tree in the descriptive language of PRINGLE )) with 
huge spreading branches and leaning trunk becomes a garden of plants. On 
its rough mossy surface are found ferns, orchids, bromeliads and cactuses. 
Not epiphytal plants alone are found in such situations, but almost any herb, 
or shrub, which grows in the neighboring soil. The most abundant tree of 
these tropic forests is doubtless Ficus segoviae associated with QOuercus germana, 
Dendropanax arboreum, Banara mexicana, Zanthoxylum Pringlei, Clethra 
Pringlei and a host of others. 
At an altitude of 2,000—3,000 feet in the neighborhood of Orizaba, several species of oak 
occur: Quercus polymorpha, Q. tomentosa and Q. obtusata, all trees of small dimensions, having 
small rigid, usually wooly leaves. At 3,000 feet, the oak trees become larger and form dense 
forests with the following oak species: Q. jalapensis, Q. calophylla (= Q. alamo), Q. polymorpha, 
Q. lanceolata, Q. Ghiesbreghtii. Beneath the shade of the oaks grow various species of wann 
maedorea and on their roots the scarlet Monotropa uniflora (= M. coceinea) and Conopholis 
silvatica (near C. americana). A variety of woody climbers occur, belonging to such genera as 
Banisteria, Paullinia, Serjania, Smilax, Rubus and Vitis. On the outskirts of the forest grows an 
elegant bamboo, Arundinaria acuminata. At an elevation of 45,000 feet higher on the moun 
tain sides, dense forests exist in which Quercus Galeottü, Q. insignis and such evergreen en 
leafless during the short continuance of the violent northerly winds) enter as important elegients, 
Many elegant epiphytes grow in these forests, such as Juanulloa parasitica, er Er: 
deana, various orchids and bromeliads?). At an altitude ranging from 6—-7,000 feet, pines begin 
———— 
1) PRINGLE, C. G.: l. c. On the Tampico Branch. Garden and Forest VI: ae En as 
2) Hemsıev, W. B.: See Gopmann & SaLvın in Bibliogr. p. 83, IV: a ee 
lation in Hooker’s Kew Journal Botany IV (1852): 321. 
