The vegetation of northern and central El Peten has been studied by
Lundell (1937), who made only passing remarks concerning the plants of
the southern part of El Peten. No floristic studies have been made
there. The following remarks are necessarily brief and are intended
only to give the reader a general picture of the forest. I have included
names of a few of the commoner trees that I recognized.
Chinaja is located in a vast expanse of unbroken rainforest. In this
forest there is a noticeable stratification of the vegetation. Three
strata are apparent; in the uppermost layer the tops of the trees are
from 40 to 50 meters above the ground. The spreading crowns of the trees
and the interlacing vines form a nearly continuous canopy over the lower
layers. Among the common trees in the upper stratum are _Calophyllum
brasiliense_, _Castilla elastica_, _Cedrela mexicana_, _Ceiba
pentandra_, _Didalium guianense_, _Ficus_ sp., _Sideroxylon lundelli_,
_Swietenia macrophylla_, and _Vitex_ sp. (Pl. 1, fig. 1). The middle
layer of trees have crowns about 25 meters above the ground; these trees
in some places where the upper canopy is missing form the tallest trees
in the forest. This is especially true on steep hillsides. Common trees
in the middle layer include _Achras zapote_, _Bombax ellipticum_,
_Cecropia mexicana_, _Orbignya cohune_, and _Sabal_ sp. The lowermost
layer reaches a height of about 10 meters; in many places in the forest
this layer is absent. Common trees in the lower stratum include
_Crysophila argentea_, _Cymbopetalum penduliflorum_, _Casearia_ sp., and
_Hasseltia dioica_.
The ground cover is sparce; apparently only a few small herbs and ferns
live on the heavily shaded forest floor. Important herpetological
habitats include the leaf litter, rotting stumps, and rotting tree
trunks on the forest floor and the buttresses of many of the gigantic
trees, especially _Ceiba pentandra_ (Pl. 2). Epiphytes, especially
various kinds of bromeliads, are common. Most frequently these are in
the trees in the upper and middle strata.
At Toocog there is sharp break between savanna and forest (Pl. 7, fig.
2). The forest is noticeably drier and more open than at Chinaja (Pl.
9). The crowns of the trees are lower, and there is no nearly continuous
canopy between 40 and 50 meters above the ground. Although _Swietenia
macrophylla_ and other large trees occur, they are less common than at
Chinaja. Especially common at Toocog are _Achras zapote_, _Brosimum
alicastrum_, and various species of _Ficus_.