Octarrhena mendumiana
Prev Taxon: Genus Oberonia section Scytoxiphium
Current Genus: Genus Octarrhena
Next Taxon: Genus Odontochilus
Octarrhena mendumiana
Octarrhena mendumiana Schuit.& de Vogel, Malesian Orchid J. 9 (2012, publ. 2011) 13, fig. 14-16
Type: Brass 9527 (holo L; iso BRI)
Synonyms:
Stems numerous, erect, tufted, forming dense, grass-like clumps to 20 cm across, 2–3 cm long, about 0.25 cm wide across the leaf-sheaths, densely many-leaved; usually only about five leaves are present in the apical part of the stem, the older leaves having fallen off. Leaves suberect, semiterete, almost needle-shaped, rigid, somewhat longitudinally twisted, channelled, 2–3.2 by 0.06 cm; sheaths overlapping, suberect, conduplicate, bilaterally flattened, dilated towards the base, c. 0.2 cm wide; apex obtuse. Inflorescences lateral, erect, 2.5–3.5 cm long; peduncle c. 1 cm long, with several bract-like peduncle-scales; rachis very densely many-flowered, 1.5–2.5 cm long; floral bracts narrowly triangular-setose, 0.27–0.33 cm long. Flowers opening widely, 0.24 cm across. Pedicel and ovary obovoid, c. 0.2 cm long, glabrous. Sepals free, concave, glabrous. Median sepal triangular-ovate, 0.15 by 0.09 cm; apex obtuse; 3-nerved. Lateral sepals ovate, 0.16 by 0.09 cm; apex obtuse; 3-nerved. Petals linear, 0.12 by 0.03 cm, glabrous; apex obtuse; 1-nerved. Lip concave, linear-oblong, 0.13 by 0.04 cm; apex fleshy, obtuse. Column very short, 0.04 cm long without the anther, glabrous; stigma slit-like, transverse, with somewhat protruding upper and lower margins; rostellum truncate, slightly apiculate; clinandrium cup-like, margins entire. Anther 0.07 cm wide, cucullate, rounded to 5-angular, bilocular; pollinia pyriform, 0.023 cm long, caudicle and viscidium not seen. Fruit not seen.
(after Schuiteman & de Vogel, 2012, publ. 2011)
Leaves , light green. Peduncle-scales and floral bracts dark brown. Flower creamy white, pedicel and ovary yellowish green.
Epiphyte on Papuacedrus in open subalpine forest and on isolated trees, locally gregarious. Usually growing in moss clumps, rooting extensively under the bark. Altitude 3225–3500 m.
Malesia (New Guinea), endemic.
Papua (Nabire and Jayawaijaya Regency); see map
Cold growing epiphyte.
August- October.
- Family Orchidaceae
- Subfamily Epidendroideae
- Tribe Podochileae
- Subtribe Thelasiinae
- Genus Octarrhena
- Species Octarrhena mendumiana
Octarrhena mendumiana is probably closest related to the widespread O. angraecoides Schltr., but that species has much larger vegetative parts with broad, laterally flattened leaves, green flowers, ovate petals, and a lip with two calli at the base. The grooved, obtuse, semiterete leaves of O. mendumiana are apparently unique in the genus. In the white flowers and tufted habit this species superficially resembles a species of Phreatia, but the strictly footless column and the narrow lip are diagnostic for Octarrhena.
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Octarrhena mendumiana
Octarrhena mendumiana Schuit.& de Vogel, Malesian Orchid J. 9 (2012, publ. 2011) 13, fig. 14-16. Drawn by Eline Hoogendijk from type: Brass 9527.