Kapok (or Silk-cotton) Tree, a tree of tropical America, Asia, and Africa. The tree grows to 100 feet (30 m) tall. Its trunk may be 9 feet (2.7 m) in diameter and is supported by buttresses usually up to one foot (30 cm) thick that may start 15 feet (4.5 m) up the trunk and extend outward as much as 30 feet (9 m). Clusters of white or rose five-petaled flowers are followed by plump, woody pods as long as eight inches (20 cm). The pods contain seeds covered with long, silky fibers. Kapok oil, which comes from the seeds, is used in making soap and cattle feed.
The fibers, called kapok, are light, each being an air-filled tube. They are also springy and waterproof. These properties make kapok useful for stuffing life preservers, mattresses, and upholstery.
The kapok tree is Ceiba pentandra of the bombax family, Bombacaceae.