Castanospermum australe (Moreton Bay Chestnut or Blackbean), the only species in the genus Castanospermum, is a flowering plant in the family Fabaceae, native to the east coast of Australia in Queensland and New South Wales, and to the Pacific islands of Vanuatu and New Caledonia.
It is a large evergreen tree growing to 40 mt tall, though commonly much smaller. The leaves are 15 cm long and 6-7 cm broad, pinnate, with 11-15 leaflets. The flowers are bicoloured red and yellow, 34 cm long, produced in racemes 6 cm long. The fruit is a cylindrical pod 12-20 cm long and 4-6 cm diameter, the interior divided by a spongy substance into one to five cells, each of which contains a large chestnut-like seed.
The seeds are poisonous, but become edible when carefully prepared by pounding into flour, leaching with water, and roasting. The timber, which somewhat resembles walnut, is soft, fine-grained, and takes a good polish, but is not durable.