Geoscience Reference
In-Depth Information
Figure 2.10 Many rainforest trees develop spikes or thorns on their trunk to discourage
herbivores.
(Photo by author.)
Cauliflory.
A characteristic of many rainforest trees and vines not commonly
found in other biomes is cauliflory. Cauliflory is the production of flowers on leaf-
less trunks, rather than on twigs or smaller branches (see Figure 2.11). In many
tropical trees and lianas, the flowers (and later fruits) are attached to short leafless
stems or spring directly from the trunk or large branches. Most of the smaller
branches and often the entire crown remain vegetative. There are several types of
cauliflory. Some plants only produce flowers on their main trunk. This is called
trunciflory. In others, flowers are limited to the base of the plant, called basiflory.
Most of the plants that display cauliflory are small to medium height, usually
16-65 ft (5-20 m), and belong to the lower canopy or shrub layers. The flowers of
cauliflorous trees are often pollinated by birds and bats. Fruits are consumed by
larger animals that may be unable to reach fruit in the canopy. These trees need
these animals for the dispersal and germination of their seeds. Some trees exhibit-
ing this adaptation develop fruits that are too heavy to be supported by branches.
Many trees in the fig family (Moraceae) display cauliflory.
Survival below the canopy depends on the plant's ability to tolerate constant
shade or adapt strategies to reach sunlight. Shrubs, vines, epiphytes, and nonphoto-
synthetic plants have developed specific strategies to reach or receive sunlight or to
do without it. Vines are an important structural feature within the tropical rainfor-
est accounting for a large portion of the forest biomass and competing for water,
light, and nutrients. Their fruits are a primary food source for tropical animals.
