Orchids of New Guinea

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Dendrobium umbellatum

Dendrobium umbellatum (Gaudich.) Rchb.f. in Walp., Ann. Bot. Syst. 6 (1861) 303.

Type: Gaudichaud 26 (Rawak) (holo P, iso G).

Synonyms:

Cadetia umbellata Gaudich. in Freyc., Voy. Uranie
Cadetia pseudoumbellata (J.J.Sm.) Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1912) 424.
Dendrobium pseudoumbellatum J.J.Sm., Bull. Dp. Agric. Indes Nerl. 15 (1908) 10.
- Type: Smith s.n. (Ambon: Hoetoe Mortetoe) (holo BO).
Dendrobium noesae J.J.Sm., Bull. Dép. Agric. Indes Néerl. 43 (1910) 41.
- Type: Herbarium collector s.n. (Noesa Kambangan, Mt. Brambang) (holo BO).
Diplocaulobium noesae (J.J.Sm.) J.B.Comber, Orchids Java (1990) 244.
Cadetia homochroma (J.J.Sm.) Schltr., Bot. Jahrb. Syst. 58 (1922) 91.
Dendrobium homochromum J.J.Sm., Repert. Spec. Nov. Regni Veg. 12 (1913) 29; Nova Guinea 12, 3 (1916) 278, t. 101, fig. 175.
- Type: Gjellerup 409; 616; 1012 (all syn BO).
Cadetia opacifolia (J.J.Sm.) Schltr., Bot. Jahrb. Syst. 58 (1922) 91.
Dendrobium opacifolium J.J.Sm., Nova Guinea 12, 4 (1916) 279, pl. 102, 176.
- Type: Bogor cult. (Branderhorst) 58 b (holo L)
Cadetia quadrangularis P.J.Cribb & B.A.Lewis, Orchid Rev. 97 (1989) 251

Rhizome very short. Stems crowded, slender, gradually a little dilated towards the apex, 3-6.5 cm by 1.5-2 mm, 1-leaved. Leaves erect, lanceolate, 3-4.5 by 0.8-1 cm, carnose, apex obtuse, unequally bidentate. Inflorescences terminal from the leaf axil, 1-flowered; peduncle 0.4 cm long. Pedicel 0.4 cm long, sparsely reversely muriculate; ovary 0.2 cm long, densely covered with reverse spine-like papillae. Flower c. 0.7 cm across. Dorsal sepal oblong, 0.38 cm by 2 mm, apex acute. Lateral sepals obliquely subelliptic, the free part 0.34 cm by 3.3 mm, apex rounded; mentum 0.15 cm long, apex slightly retuse. Petals linear, 0.43 cm by 0.3 mm, apex obtuse. Lip clawed, 3-lobed, claw oblong, inside pubescent, ciliate, c. 0.26 cm long, blade 0.33 cm long, between the lateral lobes with a semilunate pubescent swelling; lateral lobes narrowly triangular, 0.4 mm long, acute; midlobe recurved, narrowly transversely oblong, 0.08 by 0.38 cm, carnose, with an obtuse apicule. Column 0.18 cm long, pubescent below the stigma, stelidia obliquely quadrangular-oblong, lacerate at apex.
(after Smith, 1916 - as Cadetia opacifolia).

Colours:

Flower creamy white, midlobe of the lip yellowish, column purple at apex.

Habitat:

Epiphyte in rainforest. Altitude 0-400 m.

Distribution:

Java, Lesser Sunda Islands, Moluccas, Bismarck Archipelago, New Guinea.

Distribution New Guinea:

Papua (Yapen Waropen, Merauke and Jayapura Regencies); Papua New Guinea (East New Britain Province, but undoubtedly also widespread in the mainland provinces).

Map: Dendrobium umbellatum (Gaudich.) Rchb.f., distribution map.

Cultivation:

Warm growing epiphyte.

Flowering time in the wild:

Throughout the year.

Literature:

O'Byrne, P. 1994. Lowland Orchids of Papua New Guinea: 176, fig. (as Cadetia karoensis auct. non (Schltr.) Schltr.: O'Byrne).

Notes:

Dendrobium umbellatum (Gaudich.) Rchb.f. is one of several species of Cadetia in which the ovary is covered with soft, thick, spine-like hairs or papillae. These species, comprising most of section Cadetia, are all very much alike in shape, size and colour, and more work is to be done to clarify their taxonomy. It seems likely that some of the names currently accepted as 'good' species will end up in the synonymy of C. umbellata. The latter is characterised by the very broad, but quite short, midlobe of the lip.