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Cleisostoma isuaravanum

Cleisostoma isuaravanum

Cleisostoma isuaravanum Ormerod, Orchadian 16 (2008) 83 fig.

Type: C.E. Carr 10581 (holoA MES; iso A).

Stems imbricating leaf sheaths, rooting from below leaves, 11.0-17.5 by 0.7- 1.0 cm (measured across the leaf sheaths, 0.2-0.3 cm thick; internodes 0.8-1.5 cm long. Leaves fleshy, V-shaped in cross-section, ligulate, 5.4-7.5 by 1.44-1.60 cm, with acute to subacute apex; leaf sheaths striate, covering the stem, imbricate, 1-2 by 0.7- 1.0 cm, with truncate apex. Inflorescences emerging from the axils of the upper leaves, not branched, 13.5-15.0 cm long; peduncle 11.0-11.5 cm long, with 3 lax sheathing scales 0.3-0.5 cm long; rachis more or less successively flowered, 2.5-3.5 cm long; floral bracts fleshy, ovate, 0.3 by 0.21 cm wide, with acute apex. Pedicel and ovary 6-ribbed, 0.65-0.7 cm long. Median sepal hooded over the column, elliptic, 0.5 by 0.29-0.3 cm; apex obtuse. Lateral sepals reflexed, obliquely elliptic, 0.53 by 0.34 cm; apex subtruncate-obtuse. Petals porrect, obliquely oblanceolate oblong, 0.475 by 0.175 cm; apex acute. Lip spurred, 3-lobed; spur conical, c. 0.36 cm long dorsally, with obtuse apex; backwall callus bifurcate, erect, ventrally pubescent, ca. 0.22 cm long dorsally; front wall callus fused to the lateral lobes, lunate (viewed from above), front and back papillose-pubescent; lateral lobes rectangular, 0.26 cm tall, inside the front edge with a longitudinal thickening; c. 0.13 cm wide apically; midlobe ovate-lanceolate (viewed from above), obtuse, fleshy, 0.4 by 0.2 cm, at junction with sidelobes each side with an external, short, obtuse lobule or thickening ca. 0.03 cm long, median with a triangular, upward-pointing, acute basal callus. Column (including anther cap) 0.35 cm long.
(after Ormerod 2008)


Flowers with sepals and petals green blotched with pale brownish olive. Lip white, lateral lobes with t yellowish base, speckled red inside; midlobe with a broad marginal lilac band and two purple spots above the base. Column yellow-green; anther cream-colour.

Malesia (New Guinea, endemic)

Papua New Guinea(Central Province).

  • Family Orchidaceae
  • Subfamily Epidendroideae
  • Tribe Vandeae
  • Subtribe Aeridinae
  • Genus Cleisostoma
  • Species Cleisostoma isuaravanum
  • Ormerod, Notes on the Cleisostoma gjellerupii (J.J.Sm.) Garay complex in New Guinea. ,Orchadian 16 (2008 ) 82-87, fig.

Cleisostoma isuaravanum differs from C. gjellerupii in the broader (0.34 versus 0.25 cm), obliquely elliptic (not oblong) lateral sepals and a lip with rectangular lateral lobes (not triangular).

Cleisostoma isuaravanum differs from C. paludosum in the rectangular lateral lobes of the lip (not triangular), a dorsally straight front wall callus (not curved) and an upward-pointing, acute midlobe callus (not forward pointing, obtuse


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Cleisostoma isuaravanum

Cleisostoma isuaravanum Ormerod. Drawing by Paul Ormerod in Orchadian 16 (2008) 83 fig., based on the type: C.E. Carr 10581.