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Pterostylis caulescens

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, Bot. Mus. Leafl. 12 (1946) 149, pl. 21

Type: Clemens s.n. (holo AMES # 61211)

Stem flexuose, with one or two leaves. Leaves long-petiolate; blade 5.5-7.5 by 1.4-1.8 cm, elliptic or elliptic-lanceolate, acute, membranous, tapering to the petiole; petiole 2-5 by 0.2-0.3 cm, channelled, half-clasping the stem at the base. Flower terminal, solitary. Median sepal about 3 by 1 cm, lanceolate, acuminate, about 9-nerved, puberulent dorsally. Lateral sepals about 3 by 0.4-0.5 cm, lanceolate, acuminate, puberulent dorsally, connate at the base for about one third of their length or less. Petals about 3 by 0.5 cm, elliptic or elliptic-lanceolate, acute, somewhat falcate, 7- to 9-nerved, puberulent dorsally. Lip about 1.3 by 0.4 cm, narrowly oblong-elliptic, with a conduplicate ridge down the centre, papillose, originating from the apex of the column-foot, with a recurved flattened appendage at the base which is about 0.4 cm long and penicillate at the apex. Column about 1.3 cm long; column-foot about 0.4 cm long. (After Williams, 1946)


Flower flesh pink.

Epiphyte or terrestrial in mossy montane and subalpine forest; 2750 to 3450 m.

Malesia (New Guinea).

Papua (Indonesia); Papua New Guinea. See map

distribution map

Cool growing humus epiphyte, requires shaded position.

March, April, June, August, September, October.

  • Royen, P. van, Alp. Fl. New Guinea 2 (1979) 96
  • Family Orchidaceae
  • Subfamily Orchidoideae
  • Tribe Cranichideae
  • Subtribe Pterostylidinae
  • Genus Pterostylis
  • Species Pterostylis caulescens

Differs from Pterostylis papuana mainly in the lack of a basal rosette of leaves. Also the inflorescence of P. caulescens tends to be much shorter. Pterostylis caulescens usually occurs as an epiphyte, while P. papuana is normally terrestrial.


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Pterostylis caulescens

overview picture

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, habit, photo N.E.G. Cruttwell (10/76, PNG, Mt. Michael)

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, in situ, photo N.E.G. Cruttwell (9/81, PNG, Mt. Michael)

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, plant in situ, photo Jon Cara, from Papua New Guinea, Southern Highlands Prov., Tari

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, flower, photo Jon Cara, from Papua New Guinea, Southern Highlands Prov., Tari

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, flower, photo Jon Cara, from Papua New Guinea, Wesrern Highlands Prov., Mount Hagen

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, plant in situ, photo Graham Corbin, from Papua New Guinea, Southern Highlands Prov., Tari

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, flower, photo Jon Cara, from Papua New Guinea, Southern Highlands Prov., Tari

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, flower detail, photo Graham Corbin, from Papua New Guinea, Southern Highlands Prov., Tari

Pterostylis caulescens

Pterostylis caulescens L.O.Williams, habit and floral analysis, drawing N.H.S. Howcroft 64, based on Johns coll., from Mt. Giluwe