Orchids of New Guinea

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Dendrobium johannis

Dendrobium johannis Rchb.f., Gard. Chron. (1865) 890.

Type: King's Road cult. (Veitch) s.n. (Australia) (holo W).

Synonyms:

Dendrobium undulatum R.Br. var. johannis (Rchb.f.) F.M.Bailey, Syn. Queensland Fl. (1883) 509.
Callista johannis (Rchb.f.) Kuntze, Rev. Gen. Pl. (1891) 655.
Cepobaculum canaliculatum (Rchb.f.) M.A.Clem. & D.L.Jones, Orchadian 13 (2002) 486

An epiphytic herb. Stems 8-35 cm long, 0.7-1.2 cm diam., narrowly fusiform, swollen at base, leafy in apical quarter. Leaves 3-8, fleshy-coriaceous, thick in texture, linear-lanceolate, acuminate at unequally bilobed apex, 10-15 by 0.8-1.5 cm, canaliculate, articulated to tubular sheaths up to 3.7 cm long. Inflorescences 1-3, 20-30 cm long, laxly 2-20-flowered; peduncle usually shorter than rachis; bracts minute, 2-2.5 mm long. Flowers 2.5-3.5 cm across, small for section; pedicel and ovary 1.2-3 cm long. Dorsal sepal narrowly oblong or oblong-lanceolate, obtuse, 1-1.5 by 0.35-0.5 cm; lateral sepals oblong, obtuse, oblique at base, 1.2-1.8 by 0.5 cm; mentum pointing backwards, more or less parallel with ovary, 7-8 mm long. Petals reflexed-suberect, linear-spathulate, obtuse, 1-2.5 by 0.3 cm, once-twisted. Lip 3-lobed, 1.2-1.6 by 0.8-1 cm; side-lobes elliptic-oblong, rounded in front; midlobe ovate, acute, 0.45 by 0.5 cm, about half to two-thirds width of lip; callus of three fleshy ridges almost to apex of midlobe, dilated somewhat and broken above. Column very short, 3-4 mm long; anther cap not notched on dorsal surface.
(after Cribb, 1986).

Colours:

Sepals and petals yellow, suffused with dark purple or brown in apical two-thirds; lip yellow with purple venation.

Habitat:

Epiphyte in rainforest margins and near the coast.

Distribution:

South New Guinea, Northeast Australia (Queensland, islands of Torres Strait), .

Distribution New Guinea:

Papua New Guinea (Western Province).

Map: Dendrobium johannis Rchb.f., distribution map, redrawn from P. Cribb, Kew Bull. 41 (1986) 644, map 4.

Cultivation:

Warm growing epiphyte, prefers light position.

Classification:

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

Literature:

Cribb, P.J. 1986. Kew Bull. 41: 643, fig. 4C, D, pl. 8F, map 4.

Notes:

Dendrobium johannis Rchb.f. and the similar Dendrobium trilamellatum J.J.Sm. are readily recognised by their rather dwarf habit, somewhat fusiform stems bearing a few linear-lanceolate leathery leaves towards the apex, and their small yellowish or brownish flowers. Dendrobium johannis can be distinguished by its generally smaller stature and flowers which have chocolate-brown to purplish brown sepals and petals, a mentum at an acute angle to the ovary and a lip in which the midlobe is markedly narrower than the width across the side lobes.