Balsa

Ochroma pyramidale, the balsa, is a very fast-growing, soft-wooded evergreen tree of the Malvaceae (formerly Bombacaceae) native to lowland tropical forests from southern Mexico through Central America and into northern South America, and widely planted across the tropics. Reaching 20 to 30 metres tall in 10 to 15 years, it has a straight, smooth-barked trunk that may be buttressed at the base and a sparse, spreading crown. The alternate, long-petiolate leaves are large, 20 to 50 centimetres across, palmately five to seven lobed with a heart-shaped base and densely stellate-pubescent beneath. Conspicuous, solitary flowers borne at the branch tips are erect, cup-shaped, 10 to 15 centimetres long with five thick creamy white to pale yellow petals and a stout column of stamens; they open at dusk and are pollinated by bats and arboreal mammals. The fruit is an elongate woody capsule 15 to 30 centimetres long that splits into five valves to release numerous small seeds embedded in copious silky brown floss. Mature wood is the lightest commercial timber in the world.