Species Information - Dendrobium quadricarinatum

Dendrobium quadricarinatum 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): 107, fig. 229-31

Type: Leiden cult. 20030863a (de Vogel et al.) (holo L)

Synonyms:

Rhizome short, creeping. Roots filiform, flexuose, to 0.2 cm thick; glabrous. Pseudobulbs close together, ovoid-oblong, 2.5-3 by 0.8-1.2 cm, distinctly tapering to the top; 6-angled, when older slightly flattened, 6-ribbed, the ribs on the flatter side closer together; rather long covered by the dried, papyraceous, slowly decaying rhizome scales. Leaves oblong, 4.5-8.5 by 1.6-2 cm, index 2.8-4.5, thin coriaceous, somewhat stiff; base narrowed; apex with acute to rounded lobules. Inflorescences 1-3 per pseudobulb, 3.5-4 cm long; peduncle 0.7-1.3 cm long, about as long as the spathe; spathe 0.8-1.3 cm long. Pedicel and ovary c. 2.4-3.2 cm long; pedicel terete; ovary with 3 inconspicuous flat ribs. Flower c. 3 cm across. Median sepal narrowly triangular, narrowing above the middle, 1.8-2 by c. 0.3-0.35 cm; base widest just above the base; apex acute; 5-nerved; top half somewhat concave. Lateral sepals obliquely narrowly triangular; widest at the base, 1.6-2 by c. 0.7 cm; apex acute 5-nerved; top half somewhat concave; mentum conical, obtuse, 0.4-0.4 cm long;. Petals narrowly linear, 1.8-2 by 0.25 cm; apex acute; at the base 3-nerved; top half somewhat concave. Lip not clearly divided in hypochile and epichile, oblong-ligulate, when flattened 1-1.2 cm long; 5-keeled. Hypochile narrowly attached, when flattened in outline obovate, 0.55-0.7 by 0.4-0.47 cm; base c. auriculate; lateral lobes in front rounded to receding; median from halfway with a with a very low, almost straight raised midrib; keels 2, c. parallel, rather thick, in upper third of the hypochile converging and from there undulating (2 curves), gradually lowering and narrowing into the lateral keels of the epichile. Epichile narrowly triangular to ligulate, 0.5-0.55 by 0.2-0.3 cm; top truncate and retuse to acute; median with a very low, almost straight raised midrib to over halfway the epichile; inner lateral keels thin, plate-like with a swollen crest, undulating (c. 3 curves) c. as long as the median keel; outer lateral keels very low, with irregularly incised crest, to c. 1/4th of the epichile. Column in lateral view oblique triangular, c. 0.2 by 0.2 cm, 0.2 cm wide; clinandrium 3-lobulate, the lateral lobes oblique, broadly rounded with erose back margin, the median lobe subulate, tapering to the top, c. 0.1 cm long; column-foot gradually bent, in natural position 0.5- 0.7 cm long Anther subquadrate-cucullate, c. 0.1 by 0.1 cm; apex truncate.
(After De Vogel in De Vogel, Vugt & Hoogendijk 2018)

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