Family : Orchidaceae
Text © Prof. Pietro Puccio
English translation by Mario Beltramini
The species is native to Andaman Islands, Assam, Cambodia, China (Yunnan), Java, Laos, Lesser Sunda Islands, Malaysia, Moluccas, Myanmar, Sumatra, Thailand and Vietnam, where it grows on the trees or on the rocks up to about 1500 m of altitude.
The name of the genus is the combination of the Greek adjective “κοῖλος” (koilos) = hollow and of the substantive “γυνή” (gyne) = female, with reference to the concave stigma; the specific Latin name “trinervis” refers to the three ribs on the leaves.
Common names: lan thanh đạm ba gân (Vietnamese).
The Coelogyne trinervis Lindl. (1830) is an epiphytic herbaceous species, occasionally lithophytic, with ovoidal pseudobulbs grooved of yellowish green colour, spaced 2-3 cm on a creeping rhizome, 6-9 cm long and 2-3 cm broad, with at the apex two lanceolate leaves, 25-40 cm long and 2,5-3,5 cm broad, with three prominent ribs.
Terminal inflorescence from the emerging vegetation, initially erect then curved, 13-18 cm long, bearing up to 6-7 flowers, of 3,5-4,5 cm of diameter, that open at the same time, with sepals and petals of white colour, cream or pale greenish yellow and labellum with pale brown lateral lobes and white central lobe with pale brown spots at the apex.
Lanceolate sepals with pointed apex, 2-2,5 cm long and 0,6 cm broad, spatulate-linear petals, 2,2 cm long and 0,3 cm broad, trilobed labellum, 2 cm long and 1,2 cm broad, with roundish lateral lobes and oblong central lobe with obtuse apex and slightly waved margin run by two slightly waved keels, and 1,4 cm long column.
It reproduces by seed, in vitro, and by division, with each section provided of at least of 3-4 pseudobulbs.
Floriferous species and of easy cultivation requires a semi-shaded position, medium-high temperatures, 20-30 °C in summer, slightly lower in winter, with lowest night values not under the 14 °C, high humidity, 60-80%, and a slight constant ventilation. The waterings must be frequent and abundant during the growth, but allowing the substratum to dry up before giving water again, spaced, but without ever letting the compost dry for long time, in winter, utilizing rain water, demineralized or by reverse osmosis; the stagnations of water on the emerging vegetation must be avoided.Fertilizations every two weeks during the vegetative phase utilizing a balanced hydrosoluble product, with microelements, at ¼ of the dosage indicated on the package. It can be mounted on branches or pieces of bark or cultivated in pots or baskets with draining and aerated compost that may be formed by bark fragments and charcoal of small-medium size or by coir. The repottings are to be done at the appearance of the new roots when the compost begins to deteriorate.
Synonyms: Coelogyne cinnamomea Lindl. (1858); Coelogyne rhodeana Rchb.f. (1867); Coelogyne rossiana Rchb.f. (1884); Pleione rossiana (Rchb.f.) Kuntze (1891); Pleione trinervis (Lindl.) Kuntze (1891); Coelogyne angustifolia Ridl. (1897); Coelogyne pachybulbon Ridl. (1897); Coelogyne wettsteiniana Schltr. (1920); Coelogyne stenophylla Ridl. (1924).