Orchids of New Guinea

Next Taxon: Genus Dendrobium section Aporum subsection Aporum

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Dendrobium nagataksaka

Dendrobium nagataksaka Metusala, Phytotaxa 415 ( 5 ) (2019) 272, fig. 1-3

Type: Metusala RIO 9011 (holo BO)

Epiphytic herb. Roots from rhizome and base of stem, dirty white when old. Stem erect, to 83 by 1.7 cm, about cylindrical, stiff, leafy above the swollen section; lower third usually swollen. Sheath encircling stem tightly, greenish when young and becomes grayish brown when old, not long-persisting. Leaves deciduous, alternate-distichous, stiff, oblong to oblong elliptic, above waxy, 12–16 by 3.5–4.5 cm, apex obtuse or unequally 2-,lobed one lobe sometimes bidentate; coriaceous. Inflorescence 1 to several, from upper part of stem, erect to spreading, 25–36 cm long, 12–22 flowered; peduncle green, 0.4–0.5 cm in diam. at base, green; floral bract ovate to triangular, white to green. Pedicel and ovary terete, 4.5–5.5 cm long, white or light green with more green at ovary. Flower rather thin textured, 5.5–6.0 cm high, opening wide, 3.0–3.5 cm. Sepals spreading to decurved and strongly twisted, petals erect to sub-erect and twisted 1–3 times. Median sepal recurved, slightyly twisted, oblong-linear, 2.9–3.0 by 0.5 cm; apex acute to acuminate. Lateral sepals obliquely linear-triangular to oblong triangular, 3.3–3.6 by 0.6–0.9 cm; apex acute to acuminate; mentum conical, 0.9–1.0 cm long, slightly curved near apex, with obtuse or slightly retuse tip. Petals obliquely narrowly linear to linear-spathulate, 4.5–4.8 by 0.2 cm at base, gradually wider to 0.4–0.5 cm near apex; apex acute to acuminate. Lip porrect, 3-lobed, when flattened 2.7–3.0 by 1.5–1.8 cm; hypochile 1.4–1.6 cm long, the lateral lobes obliquely oblong-triangular with front margin irregular to erose, its apex obtuse; epichile obdeltoid to spathulate on a long narrow claw, 1.5–1.6 by 0.4–0.5 cm at base and gradually broader to 1.1–1.3 cm near apex, the claw c. half the length of the midlobe, its margins undulate, the apex rounded or truncate with a small acute tip; keels 3, low, simple, parallel, not raised at the tip, with acute apex. Column short, 0.5–0.6 cm long; column foot slender, about 1 cm long; stigma oblong-trapezoid; stelidia short and acute; anther cuculate, in front view about rectangular, 0.1–0.15 cm high; pollinia comma-shaped, 4 in 2 pairs, 0.1 cm long, yellow.
(after Metusala, 2019).

Colours:

Roots dirty white when old. Stem green, the basal leafless part greenish yellow. Leaves green with yellowish nerves. Inflorescence green, rachis yellowish green, floral bracts white to green. Pedicel and ovary white or light green, ovary. green. Sepals and petals white or purplish white or creamy white; mentum greenish near the apex. Lip white with purplish or reddish nerves; keels yellowish to greenish. Column white suffused with purplish or reddish at base; anther greenish or yellowish; pollinia yellow

Habitat:

Open vegetation with medium to high intensity of sunlight. Altitude 10-300 m

Distribution:

Malesia (New Guinea)

Distribution New Guinea:

Indonesia (Papua Prov., Asmat Regency, Kaimana Regency?).

Cultivation:

Warm growing epiphyte, prefers bright light

Flowering time in the wild:

In cultivation (700–800 m) in February, August - September, November

Notes:

Sometimes some flowers in an inflorescence have a deformed labellum with a midlobe which is ovate or oblong-lanceolate with acute apex.

Dendrobium nagataksaka is similar to Dendrobium gouldii, but differs in the longer epichile which it is as long as the hypochile, the obdeltoid to spathulate midlobe on a longer narrow claw (versus subspatulate), and 3 simple, low keels of equal height that terminating on the basal third of the midlobe (versus 5 keels with the central three prominent and raised at the apex on the centre of the midlobe)