pronounced: thess-PEE-zee-uh pop-ULL-nee-uh
Thespesia is from the Greek θεσπεσιος (thespesios) marvellous, divine, referring to the flower colour change from yellow to purple; populnea comes from the Latin populus, the poplar tree – like a poplar.
This is a genus closely related to cotton (Gossypium), with which it shares, among other things, the presence of gossypol glands in many plant parts. Gossypol is a chemical that helps protect the plant from predators, and which, if taken in large enough quantities, may be toxic to mammals, including humans. It is found in a very concentrated form in cotton seed, which makes the oil from that seed dangerous to use for cooking, etc., unless it is first refined.
Thespesia populnea is the most widespread species of the genus. This plant has played an important role in Polynesian culture. Probably originating in India, it is a common plant throughout the Pacific basin. Sydney Parkinson, a member of the Endeavour party, made a painting of a plant found in the Society Islands in 1769. The plant has become naturalized in Florida and the West Indies. It has taken over beaches used by nesting turtles on St John, in the US Virgin Islands. It is often found as a mangrove associate. This evergreen tree is bushy when young, but thins out with age. It can grow to 13 m or more, with a spread of up to 6 m, and grows rapidly under favourable conditions.
The bark is brown and corrugated, and the twigs are scaly. The heart-shaped, shiny green leaves are 5 – 20 cm long. They are narrower than they are long, smooth-edged, with a long petiole (5 - 10 cm). The leaf base is deeply cordate.
The flowers are cup-shaped, pale yellow, and hibiscus-like, and this often causes the plant to be mistaken for Hibiscus tiliaceus. They have a dark blotch at the base of each petal, and last for 2 or 4 days, turning maroon or pink and then dropping. They occur intermittently through the year in warm climates.
The fruit capsule is a flattened indehiscent leathery sphere. The fact that the fruits are indehiscent helps to distinguish this plant from Hibiscus tiliaceus and Thespesia populnoides. Both the capsules and the greyish brown seeds, 7–12 mm long, are buoyant, and can be dispersed over very long distances by the sea.
The species has edible fruits and flowers, and is resistant to termites. Rope has been made from the tough fibrous bark, cork from the inner bark, and the leaves have been used medicinally.
The timber is hard, and seasons well. The dark reddish brown to chocolate brown heartwood has an attractive grain and is naturally oily, so it can be highly polished; but it is often twisted and is rarely found in large pieces, so it makes only small items. It is easy to saw and work despite its wavy grain. As it does not impart a flavour, it is much used to carve wooden food bowls and utensils in Hawaii. As it is very durable ubder water, it is popular for boat-building. In Tahiti, the wood is used in the making of the to'ere (slotted wooden drum) used in traditional tribal drumming. In the Philippines and in parts of South India it is used to make a variety of musical instrumemnts. On Easter Island it was used for the rongorongo tablets. The Pitcairn Islanders make regular trips to Henderson Island to harvest the wood, which they carve into curios, from which they derive much of their income.
A yellow dye is obtained from the flowers and fruits, and a red dye from the bark and heartwood. A dark red resin exudes from the bark. Ground-up bark is used to treat skin diseases in India, and for dysentery and haemorrhoids in Mauritius. Leaves are applied to inflamed and swollen joints in South India, where also the sticky yellow sap from the young fruit is used to treat ringworm. In some places a tonic is made from the roots.
This tree is growing in the interesting group of trees by the entrance to the sewerage plant on the West Point Road.