Orchids of New Guinea

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Dendrobium shearmanii

Dendrobium shearmanii Schuit. & de Vogel, Malesian Orchid J. 4 (2009) 111, fig. 11-13

Type: Leiden cult. 20031791 (P. Shearman) (holo LAE; iso L)

2.5 by 0.3–0.4 cm , enveloped in several closely appressed, slowly decaying cataphylls, 1-leaved. Leaf very narrowly linear-semiterete, erect, more or less curved, 7–12.5 by 0.17 cm; apex almost subulate. Spathe narrow, c. 2.2 cm long; apex gradually tapering. Peduncle c. 2 cm long. Flower c. 2.5 cm wide, resupinate. Median sepal very narrowly oblong-triangular, 1.2 by 0.23 cm; apex subacute; 5-nerved. Lateral sepals at the base very oblique and much dilated, there 0.9 cm wide, upper part very narrowly triangular, 1.3 cm long; apex subacute; 5-nerved; mentum in lateral view conical-oblong, 0.9 cm long, rounded. Petals linear, 0.83 by 0.07 cm; base slightly dilated; apex subacute; 3-nerved. Lip entire, oblong, 1.3 by 0.4 cm; margins in the middle part somewhat crisped-wavy; keels two, parallel, rather widely separated, low and straight in their basal half, slightly lamellate-raised and somewhat wavy in their apical half, extending from the base of the lip to 0.3 cm below the lip apex; apical part of the lip beyond the keels triangular, acute. Column very short, 0.13 cm long; column-foot 0.9 cm long. Anther cucullate, transversely oblong in outline 0.11 cm long,; pollinia obliquely narrowly oblong, 0.08 cm long. Pedicel with ovary 1.1 cm long, terete, glabrous.
(after Schuiteman & de Vogel, 2009)

Colours:

Sepals and petals cream colour; tips pale yellow; lip reddish purple, creamy white towards the base, the keels deeper purple; column cream colour, anther light yellow; apex of the column-foot brownish orange.

Habitat:

Epiphyte in lowland rainforest. Altitude 250–300 m.

Distribution:

Malesia (New Guinea)

Distribution New Guinea:

Papua New Guinea (Southern Highlands Prov.); see map

Cultivation:

Warm growing epiphyte.

Flowering time in the wild:

In cultivation in Hortus botanicus Leiden March-September.

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Dendrobiinae
Genus Dendrobium
Section Diplocaulobium
Species Dendrobium shearmanii

Notes:

Dendrobium shearmanii Schuit. & de Vogel is similar to D. obyrnei (W.K.Harris) Schuit. & de Vogel in the relatively very large mentum and the shape of the 2-keeled lip which lacks distinct side-lobes; it differs in the very narrowly linear-semiterete, 0.17 cm wide leaves and the caespitose habit (versus leaves dorsoventrally flattened, linear, 0.3-0.5 cm wide). The only known species of sect. Diplocaulobium with leaves almost as narrow is D. scotiiforme J.J.Sm., which however has a 3-lobed lip with a farinose callus, very slender, stalk-like pseudobulbs and bidentate leaf-tips.

The position of Dendrobium shearmanii Schuit. & de Vogel in subsection Diplocaulobium is questionable.