Genoplesium formosum D.L.Jones APNI*
Synonyms: Corunastylis formosa (D.L.Jones) D.L.Jones & M.A.Clem. APNI*
Description: Terrestrial tuberous herb.
Leaf terete, 6–30 cm long by 0.15–0.30 cm wide, dark green, base reddish, lamina closely sheathing the scape, oblanceolate to subulate, 10–20 mm long and 3–4 mm wide, ending just below the first flower.
Inflorescence 15–35 cm tall, bearing 10–25 flowers in a densely crowded spike 20–40 mm long. Ovary linear-obovoid c. 5 mm long and 2 mm wide, slightly curved, green to reddish. Flowers porrect to semi-nodding, c. 5–6 mm wide, dark red to red-purple. Dorsal sepal with a truncate base, then flared to an elliptic mid portion and tapering to an acute apex, c. 6.5–7.0 mm long by 2.6–3.0 mm wide, shallowly concave, with red wash, with 3–5 darker lines, margins, entire. Lateral sepals nearly parallel, erect, becoming deflexed with age, oblong-lanceolate, c. 8.0–9.0 mm long and 1.6–2.0 mm wide, slightly gibbous at the base, margins entire, inrolled in the vicinity of the apex, apex cucullate and obtuse, without a gland. Petals porrect, ovate-lanceolate, 6.0–6.5 mm long by c. 2.5 mm wide, margins entire or with a few small cilia, apex acuminate. Labellum hinged on a short column foot, lamina obovate, c. 5.5–5.0 mm long by 2.5–2.8 mm wide, dark purple-red, shallowly curved for most of its length then sharply transversely deflexed in the apical third, tapering to an apiculate apex, margins irregular, with dark spreading filiform trichomes to 0.8 mm long. Callus extending nearly to the labellum apex, ligulate, narrowed above the middle, fleshy, dark purple-black, papillose, apex rounded to obtuse. Column c. 1.5 mm long by 1.0 mm wide. Column wings divided by a shallow sinus into subequal lobes, upper lobe short triangular with a narrowly rounded apex, light red, margins entire; lower lobe indistinct, shallower and broader than the upper, dark red, outer surface and margins densely ciliate, cilia increasing in length toward the margin, apex broadly rounded and indistinct among cilia. Anther c. 0.7 mm long with a filiform rostrum c. 0.3 mm long. Pollinarium 1.0 mm long; pollinia c. 0.8 mm long, yellow, granular.
Flowering: Recorded flowering from October to December.
Distribution and occurrence: Grows on or close to the margins of montane swamps and alongside small watercourses, on moist soils and amongst shrubs or grasses.
NSW subdivisions: ST
Genoplesium formosum can be recognised by 1) the densely crowded inflorescence with 2) relatively large (up to 6 mm width), dark flowers, 3) the shallowly divided column wings, the lower of which is ciliate on its surface and margin, 4) the apiculate labellum whose distal third is transversely deflexed, and whose margins bear spreading multicellular trichomes, 5) the ligulate callus whose surface is papillose, 6) the other floral segments lacking glands and without trichomes except for a few minute cilia on the petal margins.
Text by Description based on D.L.Jones (2001), with modification by M.A.M.Renner (10 May 2020).
Taxon concept: Jones DL (2001) Six new species and a new combination in Genoplesium R.Br. (Orchidaceae) from eastern Australia. The Orchadian 13(7): 293-307.
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