The dense forests also contain many varieties of lianas or rubber vines, huge bombax and bamboos.
Neither can it be proved that the Huns and Magyars belonged either physically or linguistically to the same section as the lianas and Ephthalites.
The most valuable of the forest flora are the lianas, notably Landolphia florida, which yield the india-rubber of commerce.
The density of the forest is greatly augmented by the cipos, or lianas, which overgrow the largest trees to their tops, and by a profusion of epiphytes which cover the highest branches.
These widely divergent conditions give to Mexico a flora that includes the genera and species characteristic of nearly all the zones of plant life on the western continents - the tropical jungle of the humid coastal plains with its rare cabinet-woods, dye-woods, lianas and palms; the semi-tropical and temperate mountain slopes where oak forests are to be found and wheat supplants cotton and sugar-cane; and above these the region of pine forests and pasture lands.