Orchids of New Guinea

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Dendrobium nitidissimum

Dendrobium nitidissimum Rchb.f., J. Linn. Soc., Bot. 15 (1876) 112.

Type: Moseley s.n. (III-1875, Admiralty Isl.).

Synonyms:

Diplocaulobium nitidissimum (Rchb.f.) Kraenzl., in Engl.
Callista nitidissima (Rchb.f.) Kuntze, Rev. Gen. Pl. (1891) 655.
Dendrobium mettkeanum Kraenzl., Gard. Chron. (1894, II) 306.
- Type: Sander cult. (Micholitz) s.n.

Rhizome creeping, short. Pseudobulbs of two types: sterile pseudobulbs short, 0.5-1.5 cm apart, 1-leaved, ovoid-fusiform to narrowly conical, 1.6-4.5 by 0.6-1.4 cm, at apex 0.2-0.4 cm diameter; flowering pseudobulb 1-leaved, 20-35 cm long, in lower 2-4 cm slightly swollen, 3-4 sided. Leaves on sterile pseudobulbs linear, 8-12 by 0.9-1.2 cm, thin coriaceous, with rounded apex, equally or unequally bilobulate; leaves on flowering pseudobulb much smaller, lanceolate, 2-3 by 0.6-0.7 cm, with rounded apex, (deeply) bilobulate. Inflorescences terminal, 1-flowered, normally 1 up to 4 in a fascicle; peduncle 2.5 cm long; spathe oblong, 1.4-2.5 by 0.3 cm. Pedicel and ovary 2-3 cm long, cylindrical. Flower 4-6 cm across, ephemeral. Median sepal suberect, narrowly triangular, 3-3.8 by 0.3 cm; base sometimes lanceolate concave; apex acute. Lateral sepals narrowly triangular, 3-3.8 by 0.5-0.7 cm; apex acute; mentum inflated-conical, 0.5 cm long. Petals suberect to recurved, linear, 2.8-3.5 by 0.1 cm; base sometimes oblong; apex acute. Lip 3-lobed near the middle, 1.2-1.5 by 0.5 cm, with two straight basal keels which are pubescent at the base and become undulating on the claw of the midlobe where they terminate in c. halfway along a narrowly elliptic, cushion-shaped, glandular-hairy callus; lateral lobes erect, free part broadly triangular, front margin erose, with acute apex; midlobe slightly decurved, spathulate or ovate with a narrow claw, margins undulating, apex variable from entire to apiculate to tridentate. Column 0.4 cm long; column-foot 0.5 cm long, at right angles to the column proper, slightly incurved; stelidia short, bidentate. Fruit cylindrical-obovoid, approximately 5-sided, 1.7 by 0.5 cm.
(mainly after O'Byrne, 1994).

Colours:

Sepals and petals pure white with pale yellow tips. Lip creamy white with a bright yellow midlobe, lateral lobes purple-spotted with purple margins, keels and callus yellow. Flowers turn lilac just before they close.

Habitat:

Epiphyte in coastal forest and lowland rainforest. Altitude 0-125 m.

Distribution:

Malesia (New Guinea), ?Solomon Islands.

Distribution New Guinea:

Papua New Guinea (Manus Island, New Britain, New Ireland).

Cultivation:

Warm growing epiphyte.

Flowering time in the wild:

July, October-February. Flowers last only a few hours and are produced 8 days after heavy rainfall (fide O'Byrne).

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Dendrobiinae
Genus Dendrobium
Section Diplocaulobium
Subsection Diplocaulobium
Subsection Diplocaulobium nitidissimum

Literature:

Lewis, B. & P.J. Cribb. 1991. Orchids of the Solomon Islands and Bougainville: 216. But see Notes
O'Byrne, P. 1994. Lowland Orchids of Papua New Guinea: 214, fig., pl.
Schlechter, R. 1912. Repert. Spec. Nov. Regni Veg. Beih. 1: 470.

Notes:

Dendrobium nitidissimum Rchb.f., the type species of the section Diplocaulolobium, is atypical in the genus, section and subsection because the plants produce two entirely different types of pseudobulbs: relatively short pseudobulbs, and much longer and very slender pseudobulbs only slightly swollen at the base. Only the tall stems, which have much smaller leaves than the short ones, are capable of flowering. There are a few species in New Guinea and Sulawesi, sometimes unrelated with very different flowers, some undescribed, which also are heterobulbous.

Diplocaulobium nitidissimum Rchb.f., as Dendrobium nitidissimum (Rchb.f.) Kraenzl., as described by Lewis & Cribb in Orchids of the Solomon Islands and Bougainville, is most probably an undescribed species. There is no mention that the plants are heterobulbous and heterofoliate, the plants are to 55 cm high, the leaves are to 20 cm by 3.2 cm, the 2 keels run to the end of the midlobe and are not undulate and there is an oblong callus on the claw of the midlobe for which no indument is described but which accordingly to the drawing Fig. 51o may be farinose. This is an undescribed species.