Common name: Ebor Greenhood
Pterostylis metcalfei D.L.Jones APNI*
Synonyms: Diplodium metcalfei (D.L.Jones) D.L.Jones & M.A.Clem. APNI*
Description: Terrestrial herb
Sterile and fertile plants dimorphic. Rosettes only in sterile plants, leaves 3–5, lamina ovate to oblong-ovate, 9–30 mm long by 7–20 mm wide, dark green, entire, apex obtuse to shortly apiculate; petioles 4–12 mm long, narrowly winged.
Flowering plants 10–30 cm tall. Scape slender, wiry, smooth. Cauline leaves 4–6, lanceolate, 15–30 mm long by 4–7 mm wide, erecto-patent, dark green; margins entire, apex acuminate; lowest cauline leaf reduced and closely sheathing. Ovary narrowly oblong-obovoid 7–9 mm long, green, smooth. Flower solitary, 23–28 mm long, translucent white striped and suffused with dark green, darkest toward the galea apex; galea gibbous at base then erect before curving forwar. Dorsal sepal 40–52 mm long by 16–20 mm wide, inflated at the base, contstricted near the middle, slightly enlarged above the middle before tapering to a filiform point 7–14 mm long, apex of dorsal sepal decurved. Lateral sepals erect, tightly embracing the galea; sinus protruding as a prominent knee in side view, internal knee angle less than 90 degrees, the upper margin horizontal or slightly raised centrally when viewed from the front; conjoined part 12–16 mm long by 8–12 mm wide, narrowed to c. 3 mm across at the base, upper margins dark green and involute, tapered into linear filiform free points 22–30 mm long erect and held parallel high above the galea. Petals obliquely lanceolate, 22–32 mm long by 4–6 mm wide, falcate, tapered distally, subacute to acute, darker green or brownish green toward apex; flange broadly obtuse, c. 1.5 mm across flat. Labellum elliptic-lanceolate,13–17 mm long by 2.5–3.5 mm wide, brown or brownish-white, distal third dark brown, brown or greenish-brown toward the base, apex obtuse; hinged on a basal ligulate claw c. 4 mm long and 1.5 mm wide, erect, curved forward in the upper third which protrudes through the sinus in the set position; labellum apex sometimes contacting the galea; lamina narrow elliptic, tapered in upper third to an obtuse apex; brown or brownish white distal third dark brown, brown or green-brown toward the base; basal appendage 4–5 mm long, linear, recurved at right angles just above the middle, apex shortly penicillate.
Distribution and occurrence: Northern New South Wales on the New England Tableland from Wongwibinda to Hernani between 1000 and 1320 m elevation, also reported from the vicinity of Nimbin.
Wet sclerophyll forest, on slopes, and tops of escarpments, among tussocks and shrubs.
NSW subdivisions: NT
Threatened species: NSW BCA: Endangered
Pterostylis metcalfei can be recognised by the combination of long-protruding labellum when set, and distinct knee in the sinus whose upper margin is horizontal and internal angle less then 90 degrees. Pterostylis metcalfei could be confused with P. elegans but the labellum is longer than the column, whereas in P. elegans the column and labellum are the same length. Pterostylis metcalfei is similar to P. abrupta and P. decurva but lacks the strong brown pigmentation on the galea hoot of those two species, and has a labellum that protrudes beyond the apex of the knee. In P. abrupta and P. decurva the galea is orange-brown to brown pigmented and the labellum apex only protrudes as far as the knee when set, not beyond it. Pterostylis metcalfei is also similar to P. obtusa but again the long protruding labellum distinguishes it, in P. obtusa the labellum apex lays below or behind the sinus knee, rather than extending beyond it.
Text by Matt A.M. Renner (13 Dec 2019) based on Jones (1997)
Taxon concept: Jones DL (1997) Six new species of Pterostylis R.Br. (Orchidaceae) from Australia. The Orchadian 12: 245–258.
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