Species Information - Dendrobium dupense

Dendrobium dupense de Vogel in De Vogel, E.F., van Vugt, R. & Hoogenfdijk, E.A.H., Dendrobium section Diplocaulobium subsection Goniobulbon (Orchidaceae) 1: The Species with 4 or 5 Keels on the Epichile, Malesian Orchid Journal Vol. 22 (2018): 99, fig. 18-20

Type: Leiden cult. 20032393 (de Vogel et al.) (holo L)

Synonyms:

Roots filiform, flexuose, to 0.1 cm thick; glabrous. Rhizome short, creeping. Pseudobulbs close together, ovate-oblong, 1.5–2.4 by 0.5–0.9 cm, slightly flattened, distinctly tapering to the top; 4-angled to 4-ribbed. Leaves oblong, 2–4.5 by 0.9–1.4 cm, index 2.2–3.2; base narrowed; apex with acute to rounded lobules. Inflorescence c. 5 cm long; peduncle c. 1 cm long. Pedicel and ovary c. 2.8 cm long; pedicel terete, to the top slightly angular, white; ovary with 3 low, broad, flat ribs with somewhat raised margins. Flower c. 2 cm across. xMedian sepal narrowly triangular, narrowed below the middle, c. 1.8 by 0.4 cm; apex slightly swollen, acute; 5-nerved. Lateral sepals strongly falcate, obliquely narrowly triangular, widest at the base, c. 1.6 by c. 0.75 cm; apex slightly swollen, acute; 5-nerved; mentum conical, obtuse, c. cm long. Petals narrowly linear, c. 1.6 by 0.17 cm; apex slightly swollen, acute; at the base 3-nerved. Lip strongly curved, oblong-ligulate, above the middle constricted, when flattened c. 1.1 cm long; 5-keeled, keels glabrous (magn. 25×); hypochile when flattened in outline c. obovate, c. 0.6 by 0.4 cm; lateral lobes in front receding, rounded; keels 2, parallel, rather thick, rather wide apart, in top 1/4 of the hypochile conniving till touching, continuing as lower, thin, plate-like, much undulating keels (c. 5 curves) up to c. 1/4 of the epichile; epichile ovate, c. 0.5 by 0.4 cm; top acute; median with a long undulating third keel; outer lateral keels short, in one or two places interrupted low keels; below in front keeled. Column in lateral view obliquely triangular, c. 0.2 by 0.2 cm; clinandrium 3-lobulate, the lateral lobes oblique broadly triangular, the median lobe broadly triangular, subulate at the top, c. 0.05 cm long; column- foot distinctly bent at c. 1/3 from the base, in natural position c. 0.6 cm long. Anther subquadrate-cucullate with at the base a rounded extension, c. 0.15 by 0.1 cm; apex truncate.
(After De Vogel in De Vogel, Vugt & Hoogendijk 2018)

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