Orchids of New Guinea

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Dendrobium antennatum

Dendrobium antennatum Lindl., London J. Bot. 2 (1843) 236.

Type: Hinds s.n. (New Guinea) (holo K).

Synonyms:

Callista antennata (Lindl.) Kuntze, Rev. Gen. Pl. (1891) 654.
Ceratobium antennatum (Lindl.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 486
Dendrobium d'albertisii Rchb.f., Gard. Chron. (1878, I) 366.
- Type: MacArthur cult. (d'Albertis) s.n. (New Guinea) (holo W).
Ceratobium d'albertisii (Rchb.f.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 486

An epiphytic herb. Stems clustered on a short rhizome, 15-75 cm tall, 1-1.5 cm diam., somewhat fusiform, usually dilated slightly and rhombic in cross section in the lower half. Leaves distichous, coriaceous to fleshy, oblong-lanceolate to ovate-elliptic, unequally bilobed at acute apex, 4-15 by 0.5-4 cm, articulated at base to sheaths 2-2.9 cm long. Inflorescences one to several, 15-35 cm long, 3-15-flowered; bracts tubular, 3-4 mm long. Flowers fragrant; pedicel and ovary 2.2-3.5 cm long, emerging 4-7 mm above the axil of the bract. Dorsal sepal oblong-lanceolate, acute or acuminate, 1.6-2.3 by 0.6-0.7 cm, recurved and often spirally twisted; lateral sepals oblong-lanceolate, acute or acuminate, 1.6-2.5 by 0.7 cm, recurved; mentum narrowly conical, 8-10 mm long. Petals linear, acute, 2.5-5 by 0.2-0.35 cm, once- to twice-twisted. Lip 3-lobed, 1.5-2.3 by 0.9-1.15 cm; side-lobes elliptic, rounded in front; midlobe circular to ovate, acute or apiculate, not recurved; callus of 5 longitudinal ridges, slightly dilated towards apex at base of midlobe. Column 5-6 mm long.
(after Cribb, 1986).

Colours:

Leaf sheaths grey. Flowers white with green or yellow-green petals and a purple- or violet-veined lip.

Habitat:

Epiphyte. From sea level to 1200 m.

Distribution:

New Guinea to Solomon Islands and Northeast Australia (Queensland).

Distribution New Guinea:

Widespread, mainly in coastal regions.

Map: Dendrobium antennatum Lindl., distribution map, redrawn from P. Cribb, Kew Bull. 41 (1986) 629, map 2, with new records added.

Cultivation:

Warm growing epiphyte, prefers light position.

Flowering time in the wild:

June to April, peaking during the dry season (fide O'Byrne).

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Dendrobiinae
Genus Dendrobium
Section Spatulata
Species Dendrobium antennatum

Literature:

Cribb, P.J. 1986. Kew Bull. 41: 628, pl. 6A-C, map 2.
Lewis, B. & P.J. Cribb. 1991. Orchids of the Solomon Islands and Bougainville: 202.
O'Byrne, P. 1994. Lowland Orchids of Papua New Guinea: 234, fig., pl.
Schlechter, R. Repert. Spec. Nov. Regni Veg. Beih. (1912) 546.
Schlechter, R., Repert. Spec. Nov. Regni Veg. Beih. 21 (1923) t. 184, fig. 690.
Smith, J.J., Nova Guinea 8, 1 (1909) 66.

Notes:

One of the most widely distributed and best known species of the section Spatulata in cultivation, Dendrobium antennatum can be readily recognised by its intermediate-sized white flowers with green or yellow-green erect petals and a purple-veined lip. It is most closely allied to the similarly coloured Dendrobium stratiotes which, however, has much larger flowers with longer petals, to Dendrobium archipelagense which has similary sized flowers which are light green and is similar in the size of the lip, but has lateral lobes which are 70-80% of the labellum length against in D. antennatum 55- 70%, and the relatively longer petals whichre more spreading, and to Dendrobium strepsiceros whose flowers are of a similar size but green or greenish yellow, a broader lip with a larger midlobe and verrucose side lobes, the lip has a five-ridged callus like Dendrobium antennatum, but the mid-ridge is noticeably dilated at its apex on the distal half of the midlobe. Dendrobium d'albertisii is considered to be merely a shorter-petalled form of Dendrobium antennatum.