Plants as agents of damage and disease may be divided into those larger forms which as weeds, epiphytes and so forth, do injury by dominating and shading more delicate species, or by gradually exhausting the soil, &c., and true parasites which actually live on and in the tissues of the plants.
Coelogyninae, 7 genera, mostly epiphytes, and inhabitants of tropical Asia.
A large number of algae again live as epiphytes or endophytes.
The density of the forest is greatly augmented by the cipos, or lianas, which overgrow the largest trees to their tops, and by a profusion of epiphytes which cover the highest branches.
Its forests are not composed of one or a few dominating species, as in the cold temperate zone, but of countless genera and species closely interwoven together - a confused mass of giant trees, lianas and epiphytes struggling to reach the sunlight.