Because there is so little light on the tropical rainforest floor, the few plants that live there cannot depend on photosynthesis for survival.


Debris in the rainforest decomposes quickly. The underlying soil is covered with just a thin layer of leaves. The continuous rain of dead leaves, flowers and twigs from the upper layers of the forest is decomposed so rapidly that it does not accumulate. After only two to three months, a fallen leaf can no longer be recognized.

Fungi, which can be found in abundant amounts in the soil and litter, are the main agents of decomposition. They feed by destroying plant tissue.

Most of the time, fungi exist as networks of tiny threads, but sometimes they form cottony wefts among rotting leaves. When conditions are right these threads inter-weave to form a strong structure, the familiar fungus, or mushroom, which appears above the ground.

Mushrooms come in a variety of shapes and colors. On gills beneath the cap of the mushroom, some threads produce beadlike growths at their tips. These develop a thick protective wall and form the dustlike spores that blow in the wind and disperse the fungus.

Devoid of chlorophyll, fungi do not feed by photosynthesis. The threads penetrate plant tissue and secrete substances that can break down the toughest plant materials to create simple foods such as sugars, which the threads absorb.

Some fungi weave threads into a mat around a living plant root so that they can obtain substances, particularly sugars and those containing nitrogen, found in the root.

The root, in turn, takes up a supply of the minerals absorbed initially by the fungus. This symbiotic association, in which both partners benefit, is called a mycorrhiza,

Because fungi live on dead material, they are known as saprophytes.

Flowering Plants


There are a few saprophytic flowering plants on the floor of the rainforest. They have no chlorophyll.. Saprophytic plants are inconspicuous and small - few are more than 8 inches (20cm) tall.


Rafflesia arnoldii, which bears the largest flower on Earth, exists among the sparse population of plants on the tropical rainforest floor. This plant is a parasite of rainforest lianas.

The rafflesias and their relatives are among the most complete parasites known. Only their flowers appear outside their host; the rest of the plant lives inside, between the wood and the bark.

Thonningia sanguinea is another parasitic plant that lives on the floor of tropical rainforests. Its flowers are rose-red and can often be seen amidst fallen leaves in the rainforests of Africa.