Thrixspermum congestum, commonly known as the cupped hairseed,[1] is an epiphytic or lithophytic orchid that forms small clumps with many thin roots, up to fifteen leathery leaves and many star-shaped white or cream-coloured flowers. This orchid occurs from Papuasia to northern Australia.
Thrixspermum congestum is an epiphytic or lithophytic herb that forms small clumps with many thin roots and flattened stems NaNmm long. It has between six and fifteen crowded stiff, leathery leaves NaNmm long and NaNmm wide. The flowers are cream-coloured or white, NaNmm long and NaNmm wide arranged on a wiry flowering stem NaNmm long. The sepals are NaNmm long and NaNmm wide, the petals a similar length but only about 2mm. The labellum is about 5mm long and 2mm wide with three lobes. The side lobes are hairy and erect, about 1.5mm long and 3mm wide, narrow, curved and pointed. The middle lobe is short, fleshy and hairy with a short, hairy spur. Flowering occurs sporadically and the flowers open from one to a few at a time.[2] [3] [4]
The cupped hairseed was first formally described in 1895 by Frederick Bailey who gave it the name Cleisostoma congestum and published the description in Proceedings of the Royal Society of Queensland.[5] [6] In 1967, Alick Dockrill changed the name to Thrixspermum congestum.[7] The specific epithet (congestum) is a Latin word meaning "collected", "dense" or "thick".[8]
Thrixspermum congestum grows on mangroves and rainforest trees in humid but airy situations. It occurs in New Guinea, the Solomon Islands, New Caledonia, Vanuatu and Australia. In Australia it is found on Melville Island and between the Iron Range and the Tully River in Queensland.