Dendrobium macrophyllum A.Rich., in D'Urv., Voy. Astrol., Bot. (1834) 22.
Type: Lesson s.n. (New Guinea) (holo P).
A medium-sized to large epiphytic herb. Pseudobulbs clustered, clavate or subclavate, rarely fusiform, up to 50 cm tall rarely more, 1.4-3 cm diam., drying yellow, 4-6-noded below leaves, (2-)3 (rarely more)-leaved. Leaves suberect, coriaceous, oblong or oblong-elliptic, obtuse, 15-31 by 3.3-9 cm, lowermost leaf often 1-3 cm below nearest leaf. Inflorescences erect, terminal, up to 40 cm long, often densely many-flowered; bracts lanceolate, acute, 1.5-2.5 cm long. Flowers rather variable in size; pedicel and ovary setosely hairy, 2.5-4 cm long. Sepals setose on outer surface; dorsal sepal oblong-ovate or oblong-lanceolate, acute, 2.1-2.6 by 0.7-1 cm; lateral sepals obliquely triangular, acute or acuminate, 2.3-2.6 by 1.2-1.4 gym; mentum obliquely conical, 1 cm long. Petals oblanceolate or oblong-oblanceolate, acute, 1.8-2.2 by 0.8-1.1 cm, with somewhat undulate margin. Lip 3-lobed, strongly recurved, 1-2 by 1.6-2.7 cm; side-lobes erect, subquadrate-flabellate, dilated above, truncate; midlobe transversely oblong, apiculate, conduplicate; callus obscurely 3-ridged, raised 2 mm at apex. Column short, 3 mm long, with two hook-like apical appendages at apex; foot 1 cm long.
(after Cribb, 1983).
Colours: Flowers yellow or greenish with purple stripes on lip side-lobes and spots or stripes on midlobe ; callus white.
Habitat: Epiphyte in forests, also lithophytic. Altitude 0 to 1700 m.
Flowering time in the wild: Throughout the year.
Distribution: Java, Lesser Sunda Islands, the Philippines, Sulawesi, Moluccas, New Guinea, Palau Islands, Solomon Islands, Vanuatu, New Caledonia, Fiji and Samoa.
Distribution in New Guinea: Papua and Papua New Guinea, widespread.
Notes: Dendrobium macrophyllum is the most widespread species in the section. It is also rather variable particularly in flower size and colouration, but is readily distinguished from all allied species with setose ovaries by its usually 3-leaved pseudobulbs, oblong-elliptic leaves, relatively narrow petals, the broad side-lobes of its lip, its conical mentum and the lack of a ligule on the column foot. In the closely allied Dendrobium polysema the flowers open more widely end the lip side-lobes always taper to a rounded apex, the petals are also usually reflexed in the open flower, and its pseudobulbs bear 2 broadly elliptic leaves.
(after Cribb, 1983).
Cultivation: Warm to intermediate growing epiphyte. Prefers a bright to lightly shaded position and humid conditions throughout the year.
INFRASPECIFIC TAXA
Dendrobium macrophyllum A.Rich. var. subvelutinum J.J.Sm., Nova Guinea 8 (1911) 552.
Differs from the typical variety in that the outside of the sepals, ovary and pedicel are very shortly subvelvety muricate rather than setose.
(after Cribb, 1983).
Colours: Flowers yellow or greenish with purple stripes on lip side-lobes and spots or stripes on midlobe ; callus white.
Type: West New Guinea, near Bivak Hollandia, Gjellerup 401 (holo BO).
Habitat: Epiphyte in coastal forest. Altitude 40 m.
Flowering time in the wild: December.
Distribution: New Guinea.
Distribution in New Guinea: Papua (Jayapura area); Papua New Guinea (uncommon, fide O'Byrne).
Notes: This variety differs from the typical variety only in lacking setae on the outside of the sepals, ovary and pedicel, these being replaced by much shorter somewhat papillate projections particularly dense upon the ovary.
(after Cribb, 1983).