Species Information - Dendrobium cromwellense

Dendrobium cromwellense 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): 94, fig. 11-13

Type: Leiden cult. 20120714 (N. & F. Juhonewe) (holo L)

Synonyms:

Roots filiform, flexuose, to 0.15 cm thick; glabrous. Rhizome short, creeping; rhizome scales somewhat longer than the pseudobulbs, soon dry and membranous, partly decaying, remaining long persistent around the pseudobulbs. Pseudobulbs close together, obliquely erect, ovoid-oblong, 2.5–3.5 by 1 cm; tapering to the top; hardly flattened, 6-ribbed. Leaves ovate- oblong, 3.8–6.8 by 1.1–1.6 cm, index c. 3.5–4.25; base narrowed; apex with acute lobules. Inflorescences (1-)3 per pseudobulb, developing in succession, 3.5–4.5 cm long; peduncle 0.8–1.0 cm long, shorter than the 1–1.4 cm long spathe. Pedicel and ovary c. 3.5 cm long; pedicel angular, white, ovary with 3 flat ribs, pale greenish. Flower c. 3 cm across. Median sepal narrowly triangular, 1.8–2.1 by c. 0.35 cm; in top half concave and slightly thickened; apex acute; 5-nerved. Lateral sepals obliquely narrowly triangular, widest at the base, c. 1.8–2.1 by c. 0.7 cm, in top half concave and slightly thickened; apex acute; 5-nerved; mentum conical, obtuse, c. 0.55 cm long. Petals narrowly linear, c. 1.9 by 0.2 cm; widest somewhat above the base; in the middle concave; in top half inside flat, outside thickened; apex acute; 3-nerved. Lip when flattened long ovate, not constricted below the middle, distinctly curved, 0.9–1 cm long; 5-keeled; hypochile when flattened in outline obovate, c. 0.5 by 0.4 cm; lateral lobes not developed; keels 2, wide apart, more or less parallel, rather thick, very minutely papillose (25x), in top 1/4 of the hypochile converging, continuing as lower, thin, plate-like, undulating keels (c. 4 curves) to the top third of the epichile; epichile when flattened more or less triangular-ligulate, widest as its base, c. 0.5–0.6 by c. 0.3 cm; top triangular, with acute tip, this tip below keeled; inner lateral keels thin, plate-like, undulating (c. 4 curves) to the top third of the epichile, there curved and laterally slanting; median keel from the top of the hypochile to almost the top of the lip; outer lateral keels inconspicuous, low, from base to c. halfway the epichile, its crest irregularly incised, all keels not papillose (50x). Column in lateral view oblique triangular, 0.15 by 0.2.5 cm, c. 2.5 cm wide; clinandrium 3-lobulate, the lateral lobules broadly triangular, the median lobule subulate, c. 0.8 cm long; column-foot gently curved, in natural position c. 0.5 cm long. Anther bell-shaped, c. 0.12 × 0.1 cm; apex truncate.
(After De Vogel in De Vogel, Vugt & Hoogendijk 2018)

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