BOMBAX, or COTTON-TREE, in botany, a genus of the monodelphia polyandria class. It has but one stylus; the stigma consists of five lobes; the capsule has five cells; and the seeds are downy. There are three species, viz. the pentandrum, the ceiba, and the heptaphyllum, all natives of the Indies. The cotton-tree grows generally above 60 feet high, and is so thick that the Indians dig canoes which hold several men out of the whole wood. There are hollows in different parts of the trunk which contain large quantities of water, which is of great use to travellers in the hot climates where there is often a scarcity of water. For the method of making cotton, see COTTON.