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Genus Oxystophyllum

Genus Oxystophyllum

Oxystophyllum Blume, Bijdr. (1825) 335


  • Dendrobium sect. Oxystophyllum ( Blume) Miq., Fl. lnd. Neerl. Bat. 3 (1855) 644. Type species: Dendrobium rigidum (Blume) Miq. non R.Br. (= Dendrobium concinnum Miq.).
  • Dendrobium subgen. Aporum (Blume) Kränzl. sect. Holophylla Kränzl. in Engl, Pflanzenr. Orch. Mon. Dendr. 1 (1910) 203 p.p. Type species: not designated.
  • Aporum Blume sect. Oxystophyllum (Bl ume) Brieger in Schlechter, Die Orchideen ed. 3, 1 (1981) 676. Type species: Aporum rigidum (Blume) Brieger, nom inval.

Epiphytes or lithophytes, erect or pendant. Roots brown, wiry, very thin. Rhizome short. Stems short to much elongated, slender, branched or not, not fleshy, densely many-leaved throughout, entirely covered by leaf sheaths. Leaves sheathing at the base, overlapping, glabrous, thick coriaceous, bilaterally flattened, with sharp edges and sharp pointed apex; leaf sheaths articulate with the leaf blade. Inflorescences terminal or laterally from the stem, very short, 1-flowered, often in small clusters. Flowers lasting at least several days, small, not opening widely, often rather fleshy, usually dark maroon, sometimes greenish or yellowish. Median sepal free, rigid. Lateral sepals obliquely triangular; mentum well-developed, not tubular in apical part. Petals free, smaller than the sepals. Lip not mobile, fleshy, entire, saccate at the base; at the apex on the abaxial side with a pointed swelling; secreting sticky liquid at the base and along the grooved upper surface. Columm shorter than the column foot; pollinia four, in pairs, attached to prominent caudicles.

Burma, Thailand, Indochina, Malaysia, Singapore, Brunei, the Philippines, Indonesia, Papua New Guinea, Solomon islands. About 30 species; in New Guinea c. 10 species.

Epiphytes in lowland, hill, and lower montane forest. Altitude 0-1700 m.

  • Family Orchidaceae
  • Tribe Dendrobieae
  • Genus Oxystophyllum
  • Lavarack, B., W. Harris & G. Stocker. 2000. Dendrobium and its relatives. Timber Press, Portland, Oregon.

While genus Oxystophyllum appears similar to species of sect. Aporum because of the overlapping, laterally flattened leaves, it is not closely related. In fact, molecular analyses independently performed by M. A. Clements and Y. P. Ng demonstrate that sect. Oxystophyllum does not even belong in the genus Dendrobium but in the genus Eria! In hindsight, this is corroborated by several morphological characters, such as the wiry brown roots. It is true that Eria should have eight pollinia, while Dendrobium always has four pollinia. Genus Oxystophyllum clearly has four pollinia, but they lack the typical shape of Dendrobium pollinia, which are always quite narrow and cohering in two pairs, while they are much thicker and less clearly paired in Oxystophyllum. Fortunately, these revolutionary developments will have little effect outside the realm of taxonomy, since the ornamental qualities of genus Oxystophyllum are negligable. The small flowers, often mercifully hidden on the underside of the stems, are most often very deep maroon, but they can also be greenish tinged with dull red. The lip is provided with a more or less conical wart on the underside near its apex.

In New Guinea genus Oxystophyllum contains the following 10 species:

Oxystophyllum acianthum
Oxystophyllum araneum
Oxystophyllum atropurpureum
Oxystophyllum bipulvinatum
Oxystophyllum buruense
Oxystophyllum excavatum
Oxystophyllum govidjoae
Oxystophyllum nitidiflorum
Oxystophyllum subsessile
Oxystophyllum torricellianum
Oxystophyllum tumoriferum

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Genus Oxystophyllum

Oxystophyllum sp., habit, photo J.B. Comber, based on John Kirkley cult. (ex PNG, Wabag)

Genus Oxystophyllum

Oxystophyllum sp., flowers, photo J.B. Comber, based on John Kirkley cult. (ex PNG, Wabag)

Genus Oxystophyllum

Oxystophyllum sp., habit, photo N.E.G. Cruttwell, based on Cruttwell (5/81, PNG, Gahavasika)