Orchids of New Guinea

Dendrobium comatum

Dendrobium comatum (Blume) Lindl., Gen. Sp. Orchid. Pl. (1830) 76.

Synonyms:

Desmotrichum comatum Blume, Bijdr. (1825) 330.
- Type: Blume ?? s.n. (Buitenzorg, mountains) (holo L ???).
Flickingeria comata (Blume) A.D.Hawkes, Orchid Weekly 2 (1961) 453.
Callista comata (Blume) Kuntze, Rev. Gen. Pl. (1891) 654.
Ephemerantha comata (Blume) P.F.Hunt & Summerh., Taxon 10 (1961) 103.
Dendrobium criniferum Lindl., Edwards's Bot. Reg. (1844) Misc. 41.
- Type: Duke of Northumberland cult. (Power) s.n. (Ceylon) (holo K-LINDL).
Desmotrichum criniferum (Lindl.) Kraenzl., in Engl., Pflanzenr. IV. 50. II. B. 21 (1910) 348.
Ephemerantha crinifera (Lindl.) P.F.Hunt & Summerh., Taxon 10 (1961) 103.
Dendrobium fasciculatum F.M.Bailey, The Garden (1905) 201 (nomen).
Dendrobium thysanochilum Schltr., in K.Schum. & Lauterb., Nachtr. Fl. Deutsch. Schutzgeb. Südsee (1905) 152; Repert. Spec. Nov. Regni Veg. Beih. 21 (1923) t. 152, fig. 571.
- Type: Schlechter 13720 (New Britain) (holo B).
Desmotrichum thysanochilum (Schltr.) Carr, Bull. Misc. Inform. Kew (1934) 380.
Ephemerantha thysanochila (Schltr.) P.F.Hunt & Summerh., Taxon 10 (1961) 106.
Dendrobium comatum (Blume) Lindl. var. papuanum J.J.Sm., Nova Guinea 8, 3 (1911) 551.
- Type: Bogor cult. 90 (Lorenz Exp. (Djibdja)); (Branderhorst (1909)) 26 B;.
Ephemerantha comata (Blume) P.F.Hunt & Summerh. var. papuana (J.J.Sm.) P.F.Hunt & Summerh., Taxon 10 (1961) 103.

Rhizome erect or pendent, up to 1 m long, branching. Shoot with the uppermost internode swollen to form a pseudobulb. Pseudobulbs clavate, becoming progressively smaller the further they are from the base of the rhizome, up to 17 cm long, 3 cm in diameter, 1-leaved at apex. Leaves similarly becoming progressively smaller the further they are from the base of the rhizome, elliptic to ovate, 6-22 by 3-10 cm. lnflorescences arising terminally from the leaf axil as well as laterally from the nodes of the stems, very short, 1-flowered, often fascicled. Pedicel with ovary 2-3 cm long. Flowers opening widely, 2.5-3 cm across, faintly scented. Dorsal sepal oblong, acute 1-1.5 cm by 3-5 mm. Lateral sepals narrowly triangular, acute, 1-1.5 cm by 4-6 mm; mentum c. 6 mm long, conical. Petals linear, 1-1.5 cm by 1-1.5 mm. Lip 3-lobed below the middle, longer than the sepals, 1.3-1.9 cm by 6-8 mm, the disc with three parallel, crenate keels which extend to the apex of the midlobe, the lateral keels strongly undulate on the midlobe; lateral lobes triangular with erose margins, midlobe shortly clawed, linear, margins undulate, crenate, apex obtuse, fringed with thick, 5-6 mm long hairs. Column 4.5 mm long, foot 6 mm long.
(after Lewis & Cribb, 1991, and O'Byrne, 1994).

Colours:

Cream to pale yellow with or without pale purple spots, with a cream to yellow lip.

Habitat:

Epiphyte in rainforest, swamp forest, coastal forest, and savannah margins. Altitude 0 to 850 m.

Distribution:

Sri Lanka, continental southeast Asia, Taiwan, Peninsular Malaysia, Singapore, Sumatra, Java, Borneo, Sulawesi, ?Lesser Sunda Islands, Moluccas, The Philippines, New Guinea, Bismarck Archipelago, Australia, Solomon Islands, Vanuatu, New Caledonia, Fiji, Samoa.

Distribution New Guinea:

Papua (Waigeo Island; Biak-Numfor, Merauke, and Jayapura Regencies); Papua New Guinea (Western, Gulf, East Sepik, Madang, Morobe, and Central Provinces; Manus, New Britain, New Ireland).

Map: Dendrobium comatum (Blume) Lindl., distribution map.

Cultivation:

Warm growing epiphyte, requires a bright position and watering throughout the year.

Flowering time in the wild:

Throughout the year, more frequent in the wettest season. Flowers open 9-10 days following heavy rainfall and last 8-10 hours (fide O'Byrne).

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Dendrobiinae
Genus Dendrobium
Section Crinifera
Species Dendrobium comatum

Literature:

Lewis, B. & P.J. Cribb. 1991. Orchids of the Solomon Islands and Bougainville: 191, fig. 54, pl. 11E.
O'Byrne, P. 1994. Lowland Orchids of Papua New Guinea: 220, fig.
Schlechter, R. 1912. Repert. Spec. Nov. Regni Veg. Beih. 1: 454.
Smith, J.J. 1905. Orchid. Java: 313.
Smith, J.J. 1913. Bull. Jard. Bot. Buitenzorg II, 9: 59.

Notes:

Dendrobium comatum (Blume) Lindl. is a most distinctive orchid because of the fringed midlobe of the lip, while its growth habit is unusual as well. Initially the plants form a number of slender, crowded pseudobulbs, later a tall, erect, stem-like, branching rhizome is formed which carries much smaller pseudobulbs at large intervals, the pseudobulbs becoming progressively smaller away from the base.