Orchid Information - Genus Trachoma

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Genus Trachoma

Trachoma Garay, Bot. Mus. Leafl. 23 (1972) 207

Synonyms:

Genus Parapteroceras Aver., Bot. Zhurn. 75 (1990) 723
Genus Tuberolabium Yamamoto, Bot. Mag. (Tokyo) 38 (1924) 209

Monopodial epiphytes. Stem short to elongated. Leaves few to several, arranged in two rows, sheathing at the base, glabrous, deciduous, duplicate, leathery. Inflorescence lateral, a many-flowered raceme. Flowers either appearing in successive clusters or simultaneously along the whole inflorescence, rather small, ephemeral or not, resupinate. Sepals free. Petals free, somewhat narrower than the sepals. Lip with or without spur, more or less sac-shaped, without callosities, not mobile. Column-foot present or absent. Pollinia 2, entire or with a short slit, solid, caudicles present or absent, stipe present, short, viscidium present.

In New Guinea genus Trachoma contains the following 2 species:

Tuberolabium papuanum
Tuberolabium rhopalorrhachis

Distribution:

Southeast Asia, Malaysia, Indonesia, the Philippines, Papua New Guinea, Australia. About 20 species; in New Guinea about 2 species.

Habitat:

Epiphytes in lowland forest.

Classification:

Subfamily Epidendroideae
Tribe Vandeae
Subtribe Aeridinae
Genus Trachoma

Notes:

Members of this genus of small monopodial epiphytes are often called Saccolabium, but as currently understood true species of Saccolabium occur only in Java and Sumatra. Tuberolabium is characterised by the very fleshy, sac-shaped, immobile lip, without callosities or other ornaments inside, and by the two pollinia. Frequently seen in amateur collections.