LIANAS
It is the vines and loops of lianas (woody climbing plants ), slung between trees that confer an air of mystery often associated with rain forests. Although climbing plants are found in many plant families, the majority are found in the tropics They have evolved very successful ways of competing for light in a habitat dominated by tall trees. In contrast to epiphytes, which perch on their competitors, lianas and vines wind and clasp their up the trees, all the while rooted in the soil of the forest floor.

About eight percent of the plant species in lowland rainforests are climbers. They show different approaches to the problem of getting up to the light. The simplest is to have a barbed stem and to use brute force, thrusting upward and gaining purchase by thorns which hook on to the surrounding vegetation. Rattans (climbing palms), which can reach 200 meters (650 feet), in length, use this technique. They also have long, whip-like extensions to their new leaves which do not unfurl until the "whip" has lashed itself to the next support.

An alternative approach is used by the climbing aroid group (genera of the arum family Araceae). They produce two kinds of roots: short ones put out a right-angles to the stem, which develop adhesive hairs when they make contact with the climbing surface, and long feeding roots which may dangle in mid-air initially, but branch profusely as soon as they encounter the soil.

Another approach is to put out tendrils from leaves or stems, common among lianas such as Leea, Cissus, and Passiflora species. An outstretched tendril moves away from the light and makes sweeping movements in slow-motion as it searches for a support. Brushing against another plant stimulates it to curl. The response is rapid: the tendril f one tropical American gourd curls within 20 seconds of contact and completes its first coil in four minutes, the tissues thickening as it does so to strengthen its grip.

A number of tropical climbers have different juvenile and adult forms. Juvenile foliage may differ from the adult in size, shape, or coloring. In several species of Monstera, Ficus, Hoya, and Marcgravia, the juveniles are known as shingle plants because their leaves overlap like tiles on a roof. This habit reduces water loss to a minimum. The leaves are small, clamped to the host tree's bark and have pores only on the undersurface, so any moisture that is lost remains trapped under the leaf. As soon as shingle plants reach the light, the foliage changes dramatically, developing long stalks and large blades: flowering and fruiting then begin.