others (plates 3- 10– 15). Bark is often splotchy, with pale
and dark patches. And many tropical trees have bark
adorned with lichens and various kinds of small plants
(called epiphylls, discussed below). Tropical tree bark
may be thin and peeling, but on some trees it can be thick
and deeply ridged (and the wood inside may be very
hard— remember that wood- eating termites abound in
the tropics). There is much variability. Bark is therefore
not usually a good means of identifying a tree, as many
different species may have similar- appearing bark. Some
trees, however, such as the Chicle (Manilkara zapota)
of Central America, have distinctive bark. Chicle bark
is black and vertically ridged into narrow strips, with
the inner bark red, and yields white resin (the original
source of the latex base from which chewing gum was
manufactured).CaulifloryMany tropical trees exhibit a characteristic called
cauliflory, in which the flowers and subsequent fruits
abruptly grow from the trunk, rather than from the
canopy branches. Cauliflory generally does not occur
outside of the tropics. Cacao (Theobroma cacao; plate 3-
16), from which chocolate is produced, is a cauliflorous
understory tree. Some trees may be cauliflorous due to
the large size and heaviness of the fruits they produce,
the weight of which could not be supported on thin
outer branches (though it is equally arguable that the
opposite may be the case— the fruits may have grown
large and heavy because they grow from the trunk,
not the outer branches). The presence of cauliflorousPlates 3- 10– 3- 15.These six examples demonstrate the variability
in bark characteristics evident in tropical forests. The photos
were taken within a stretch of about 50 m (165 ft) along a
floodplain forest trail in southern Brazil. Photos by John Kricher.
Plate 3- 16. The ripe cauliflorous fruits of the Cacao tree.
Photo by Scott Shumway.
Plate 3- 17. These flower clusters are cauliflorous, growing
directly from the branch rather than the branch tip.
Photo by John Kricher.44 chapter 3 rain forest: the realm of the plants