Orchids of New Guinea

Prev Taxon: Genus Bulbophyllum section Hoplandra

Current Genus: Genus Bulbophyllum section Hyalosema

Next Taxon: Genus Bulbophyllum section Hymenobractea

Prev Species: Bulbophyllum tricanaliferum

Jump:

Next Species: Bulbophyllum urosepalum

Bulbophyllum unitubum

Bulbophyllum unitubum J.J.Sm., Nova Guinea 14 (1929) 478, pl. 78, fig. 122

Type: Thomsen 875 (holo BO, also alc.; iso L sterile)

Rhizome elongated, creeping, rooting, terete, slightly more than 0.3 cm diam. Pseudobulbs c. 2-3 cm apart, making an acute angle with the rhizome, sublinear, to the apex gradually attenuate, in cross-section rhombic, in front longitudinally bichannelled, c. 5.3 by 0.9 cm; 1-leaved. Leaf shortly petiolate, lanceolate, apex recurved (deficiente); base narrowed in an acuminate petiole; midrib above grooved, underneath obtuse prominently, margins slightly recurved acutisque, coriaceous, in total c. 12-14.5 cm long; petiole 1.4-1.7 by 2.85 cm. Inflorescences from the nodes of the rhizome, fascicled, erect, 1-flowered; peduncle terete, c. 13.7 cm long; in basal half small sheaths c. 5 tubular upper enlarging laxioribup to the with. Floral bract tightly tubular, acuminate, acute, c. 1.2 cm long. Flower large. Median sepal from the base oblong-ovate, concave, elongated in a tail, margins incurved and contiguou,s tubular extended; nerves 7, outer ones branched, inside prominent; margins densely puberulous, dorsally papillose, almost 9 cm long; wide part c. 2.5 by 1 cm, tail 0.2 cm diam. Lateral sepals shortly decurrent on the column-foot, obliquely linear, gradually narrowed to the apex; base somewhat dilated, channeled, inside on the margins shortly patent puberulous, dorsally papillose, 4-nerved, c. 7 by 0.6 cm in the basal part. Petals very small, inserted between the sepals, porrect, appressed, gradually passing in a thin filiform top, 0.9 cm long; base obliquely triangular convex, somewhat decurrent along the column-foot; 3-nerved; terminal globule 0.1 cm diam., with fairly conspicuous papillae. Lip small, mobile, curved, fleshy, weakly 3-lobed; callus triangular convex, not acute margin to base, keels 2 longitudinal rather inconspicuous in mid-lobe, margins parallel decurrent and in front apex obsolete confluent1.bus, fascia longitudinal wide pilorum rigidrum in the basal part shortly appressed torumque above longerum erect-patentumque between ribs up in the middle mid-lobed, hairs upper with the apex lobe almost reaching, above entirely papillose; underneath with a thickening in base triangular-dilated applanataque with, when not flattened 0.5 cm long; over the lateral lobes 0.37 cm wide, lower part transversely quadrangular with very short incurved rounded lateral lobes, concave, papillose, mid-lobe recurved, with lateral lobes angles obtuse, making, subelliptic-oblong with, margins laterally slightly curved, apex rounded-truncate, transversely rugulose, when not flattened 0.38 by 0.26 cm. Column short, thick, especially with the apex slightly incurved, laterally compressed, dorsally convex; underneath strongly concave with, margins a the middle of the stigma up in the middle Column-foot conspicuously roundeddilated, rib longitudinal obtuse in a hollow, 0.4 cm long; clinandrium deeply concave, apex oblong, truncate sinibus high oblong, ab auricles as long as trapezoids obliquely truncate angulo posterior acute anguloin front rounded the middle with a tooth acute instructis separated by. Anther cucullate, subglobose, apex in appendage large, saddel-shaped tranverse quadrangular with the apex slightly recurved, underneath concave extended; base bilobed, 0.18 cm long. Pollinia 4, strongly unequal; outer ones semiovate, apex obliquely truncate, outside convex, inside flat, 0.12 cm long; the inner ones much smaller.; stigma deeply concave, longitudinal, elliptic; column-foot making an obtuse angle with the ovary, apex free, slightly incurved, on either side rounded-dilated, truncate, 0.5 by 0.28 cm wide apex. Ovary terete, high, 6-grooved, c. 1.25 cm long; pedicel terete, c. 2.5 by 0.85 cm above the base articulate. (After Smith, 1929)

Colours:

Flower yellow with red streaks.

Habitat:

Epiphyte in lowland forest.

Distribution:

Malesia (New Guinea).

Distribution New Guinea:

Papua (Indonesia); see map

Distribution of Bulbophyllum unitubum in New Guinea

Cultivation:

Warm growing epiphyte.

Flowering time in the wild:

September.

References:

O'Byrne, P., Lowland Orchid. Papua New Guinea (1994) 444, fig.

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Bulbophyllinae
Genus Bulbophyllum
Section Hyalosema
Species Bulbophyllum unitubum

Notes:

There are 3 forms known under the name Bulbophyllum unitubum.

Bulbophyllum unitubum proper has large flowers, globular appendages to the petals with small low warts on the surface, and the lip has a very bushy patch of hairs. These are represented on this website by the drawings by J.J. Smith (the type Thomsen 875), Peter O’Byrne and Neville Howcroft.

A second form has large flowers, globular appendages to the petals which are at the base rather flattened amd have relatively long spines on the surface, and the lip has also a bushy patch of hairs. This is represented on the website by the photograph by Malcolm Perry

A third form has smaller flowers, petals which are twice as long as the lip with globular appendages with small warts on the surface similar to the first form, and the lip has a patch of silky, flattened hairs. This is represented on the website by the photograph by Ed de Vogel.

Study of this subgroup of section Hyalosema should bring further clarification of the status of these differences in character states, and decide if these forms should be recognised at species level or as subgeneric entities..