Orchids of New Guinea

Next Taxon: Genus Dendrobium section Aporum subsection Aporum

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Dendrobium annulatum

Dendrobium annulatum Juswara, Schuit. & Champion, Phytotaxa 414 (2019) 151 – 155 , fig. 1–3

Type: Champion WP14 (holot BO; iso BO, spirit, K herbarium, spirit)

Roots smooth, c. 0.1 cm diam. Stems crowded, simple, erect, c. 46 by 0.4 ̶ 0.6 cm over the leaf-sheaths. Leaves (narrowly) ovate-lanceolate, 6–10 by 0.8–2.0 cm; leaf sheath tubular, 1.5 ̶ 2.2 cm long, coarsely irregularly warty, the mouth broadly and obliquely swollen, opposite the leaf with a short, triangular lobe; leaf blade apex unequally bilobed with obtuse tips;. Inflorescences 2-flowered, piercing a leaf-sheath opposite and just below a leaf blade; peduncle covered by a spathe 0.7–1 cm long. Pedicel and ovary clavate, 6-ribbed, 0.91 cm long; in cross-section triangular. Flowers opening widely. Median sepal narrowly triangular, 3.8 by 0.6 cm; apex acuminate; glabrous. Lateral sepals obliquely narrowly triangular, falcate, 3.4 by 0.9 cm; apex acuminate glabrous; mentum at right angle to ovary, 0.6 cm long, open in front, its apex retuse, in lateral view obtuse. Petals linear-oblong, slightly falcate, 3.4 by 0.5 cm; apical margins incurved; apex acuminate. Lip 3-lobed, when flattened XX by XX cm; hypochile 0.45 by 0.23 cm, lateral lobes erect, inside with flattened, hair- like projections, some of which are connate at the base forming lamellae, free parts of the lateral lobes glabrous, in front obliquely triangular, falcate, with acuminate tip, with 1 keel continuing on the very base of the epichile, smooth, slightly undulating; epichile in natural position strongly recurved, when flattened in outline broadly ovate-oblong, 10.7 by 7.5 mm, its margins lacerate, its apex forming an acute, triangular tooth, upper surface with dense hair-like, laterally flattened and in part antler-like branched projections to about 0.3 cm long. Column 0.47 cm long; stigma longer than wide, subrectangular; clinandrium margins denticulate; column foot at right angle to the column, 0.57 cm long, smooth; anther helmet-shaped, 0.18 cm long and wide, glabrous; pollinia 4, in 2 pairs, narrowly oblongoid, 0.17 cm long. Fruit not seen.
(after Juswara, Schuiteman & Champoin 2019).

Colours:

Roots with green tips. Leaves above deep green or purplish green, below purplish. Flowers bright golden yellow. Pedicel and ovary light yellowish green. Lateral lobes of the lip with few reddish spots along basal margins. Column creamy yellow, the margins, in front and on the column-foot golden yellow suffused with red-purple, margins of clinandrium with a red-purple blotch, anther creamy yellow, pollinia white.

Habitat:

Not known

Distribution:

New Guinea (endemic).

Distribution New Guinea:

Indonesia (Tanah Papua). See map

Cultivation:

Cool growing epiphyte.

Flowering time in the wild:

Not known

Classification:

Family Orchidaceae
Subfamily Epidendroideae
Tribe Dendrobieae
Subtribe Dendrobiinae
Genus Dendrobium
Section Grastidium
Species Dendrobium annulatum

Notes:

Dendrobium annulatum Juswara, Schuit. & Champion is similar to Dendrobium goodallianum de Vogel, Winkel & Vugt but in the latter species the epichile is more centrally and sparsely hairy (versus hairy all over and more densely so), and the hairs are thinner, while the lateral lobes are truncate, (versus acuminate), the flower colour is white tinged lilac (versus golden yellow, and in the absence of coarsely irregularly warts and a swollen apical ring on the leaf sheath (versus warts and ring present

Dendrobium annulatum Juswara, Schuit. & Champion is similar to Dendrobium gjellerupii J.J.Sm. in the warty leaf sheaths, but in the latter species the warts are smaller and less irregular, and the apical part of the sheath is not swollen into a smooth ring (versus a swollen ring is present) and the sepals are outside warty (versus smooth) and the lip is subentire (versus 3-lobed)