Prev Taxon: Genus Thrixspermum section Thrixspermum
Current Genus: Genus Trachoma
Next Taxon: Genus Trichoglottis
Prev Species: Trachoma papuanum
Trachoma rhopalorrhachis (Rchb.f.) Garay, Bot. Mus. Leafl. 23, 4 (1972) 208
Basionym: Dendrocolla rhopalorrhachis
Small epiphyte; stems erect or suberect, 2-15 cm long, with 2-7 leaves in upper part, not or sparsely branching. Leaves 5-12 by 1.5-2.5 cm, oblong to lanceolate, thick, leathery, apex variable, obtuse to acute, entire to distinctly bilobulate. Inflorescence usually arising below the lowest leaves, usually horizontal to erect, up to 5-10 cm long, a densely many-flowered raceme with the flowers opening in successive clusters; peduncle 1-1.1 cm long, rachis gradually elongating as more flowers are produced, swollen, 0.4-05 cm diam. Flowers widely opening, up to 1.4 cm wide, short-lived. Median sepal 0.9 by 0.3 cm, oblong, acute. Lateral sepals similar but somewhat oblique. Petals 1 by 0.2 cm, linear-ligulate, with erose margins, apex acute. Lip spurred, weakly 3-lobed; lateral lobes about 0.2 cm below the lip apex, obliquely oblong, very thick, between the lateral lobes and the mid-lobe with a small very fleshy lobule; mid-lobe small, porrect, conical, fleshy; spur 0.1 cm long, in the concave center of the lip, pointing downwards, conical, laterally flattened, obtuse. Column 0.2 cm long, narrow, with very short acute stelidia. (After O’Byrne, 1994)
Note: We are unable to see significant differences between Trachoma speciosum D.L.Jones & al.and Trachoma rhopalorrhachis (Rchb.f.) Garay so we consider them conspecific.
Sepals and petals creamy white with a brownish purple transverse bar near the base, lip white with an orange-yellow patch just below the mid-lobe.
Epiphyte in various types of lowland forest, including savanna and limestone hill forest; 40 to 600 m.
Malesia (Peninsular Malaysia, Sumatra, Java, Borneo, ?Sulawesi, Moluccas, New Guinea, Philippines), Thailand, ?Laos, Vietnam, Australia.