Thrixspermum Lour.,
Fl. Cochinch. 2 (1790) 519
Monopodial epiphytic or sometimes terrestrial plants. Stem short to much elongated. Leaves few to many, distichous, sheathing at the base, glabrous, deciduous, duplicate, leathery. Inflorescence lateral, a dense, few- to many-flowered raceme, with the flowers opening in succession. Bracts often laterally flattened and then distichous. Flowers small to rather large, ephemeral, resupinate, usually whitish or yellowish, often with brown spots. Sepals free. Petals free, usually fairly similar to the dorsal sepal but often slightly narrower. Lip without spur, but more or less saccate at the base, not mobile, in the centre usually with a callus. Column-foot present. Pollinia 4, unequal, arranged in two bodies, solid, caudicles absent, stipe present, viscidium present.
Distribution
Sri Lanka, tropical continental Asia, Malaysia, Indonesia, the Philippines, Papua New Guinea, Australia, Pacific islands, east to Samoa; about 140 species.
Distribution in the Philippines
Luzon (Ilocos Norte, Mt. Province, Bontoc, Benguet, La Union, Nueva Vizcaya, Pampanga, Zambales, Bataan, Rizal, Laguna, Tayabas, Albay, Camarines, Sorsogon), Polillo, Mindoro, Palawan, Balabac, Panay, Negros, Cebu, Siquijor, Bohol, Leyte, Samar, Camiguin, Mindanao (Zamboanga, Lanao, Bukidnon, Surigao, Agusan, Davao), Basilan; 23 species.
Habitat
Epiphytes in lowland and montane forest, also in plantations and on isolated trees. 1 species [T. amplexicaule (Blume) Rchb.f.] terrestrial among shrubs in swampy vegetation.
Notes
A genus with often rather attractive, but very short-lived flowers. Most are easily recognised by the inflorescences with flattened bracts arranged in two rows, with the flowers appearing one-by-one in succession (but compare Pennilabium). Another group of species lacks such characteristic bracts; they have flowers rather similar to those of Chiloschista (a genus not yet found in the Philippines), but with an immobile lip. Not very common in cultivation.