Orchids of New Guinea

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Trachoma rhopalorrhachis

Trachoma rhopalorrhachis (Rchb.f.) Garay, Bot. Mus. Leafl. 23, 4 (1972) 208

Synonyms:

Dendrocolla rhopalorrhachis Rchb.f., Bonplandia 5 (1857) 40
- Type: Zollinger s.n. (Java, 'Bandong' = Bandung) (holo W)
Thrixspermum rhopalorrhachis (Rchb.f.) Rchb.f., Xenia Orchid. 2 (1868) 121
Sarcochilus rhopalorrhachis (Rchb.f.) Rchb.f. in Walp., Ann. Bot. Syst. 6 (1861) 500
Saccolabium rhopalorrhachis (Rchb.f.) J.J.Sm., Orchid. Java (1905) 644
Tuberolabium rhopalorrhachis (Rchb.f.) J.J.Wood, Nordic J. Bot. 10 (1990) 482
Sarcochilus brachyglottis Hook.f., Fl. Brit. Ind. 6 (1890) 34
- Type: King s.n. (holo K?)
Thrixspermum brachyglottis (Hook.f.) Kuntze, Rev. Gen. Pl. (1891) 682
Dendrocolla brachyglottis (Hook.f.) Ridl., Fl. Malay Penins. 4 (1924) 189
Trachoma speciosum D.L.Jones, B.Gray, M.A.Clem. & J.J.Wood, Austral. Orchid Res. 1 (1989) 145
- Type: ANBG cult. (Butler 408 = M.A. Clements 3643) s.n. (Australia, Queensland, Cook Distr., McIlwraith Ra., Leo Creek) (holo CBG)
Tuberolabium speciosum (D.L.Jones & al.) J.J.Wood, Nordic J. Bot. 10 (1990) 482
Parapteroceras speciosum (D.L.Jones & al.) Szlach., Ann. Bot. Fennici 40 (2003) 67

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.

Colours:

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.

Habitat:

Epiphyte in various types of lowland forest, including savanna and limestone hill forest; 40 to 600 m.

Distribution:

Malesia (Peninsular Malaysia, Sumatra, Java, Borneo, ?Sulawesi, Moluccas, New Guinea, Philippines), Thailand, ?Laos, Vietnam, Australia.

Distribution New Guinea:

Indonesia (Papua), Papua New Guinea. See map

Flowering time in the wild:

February, April.

References:

Smith, J.J., Orchid. Java, Fig.-Atl. (1914) fig. 479, as Saccolabium rhopalorrhachis (Rchb.f.) J.J.Sm.
Howcroft, N, Orchadian 3 (1969) 54, fig., as Tuberolabium speciosum (D.L.Jones & al.) J.J.Wood
O'Byrne, P., Lowland Orchid. Papua New Guinea (1994) 534, fig., as Trachoma speciosum D.L.Jones, B.Gray, M.A.Clem. & J.J.Wood

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Vandeae
Subtribe Aeridinae
Genus Tuberolabium
Species Tuberolabium rhopalorrhachis