Pandanus is a genus of monocots with about 600 known species. Plants vary in size from small shrubs less than 1 metre tall, up to medium-sized trees 20 metres tall, typically with a broad canopy and moderate growth rate. The trunk is stout, wide-branching, and ringed with many leaf scars. They commonly have many thick prop roots near the base, which provide support as the tree grows top-heavy with leaves, fruit, and branches. The leaves are strap-shaped, varying between species from 30 centimetres up to 2 metres or more long, and from 1.5 centimetres up to 10 centimetres broad.