Genoplesium arrectum D.L.Jones APNI*
Synonyms: Corunastylis arrecta (D.L.Jones) D.L.Jones & M.A.Clem. APNI*
Genoplesium sp. aff. arrectum (Mt Kaputar) APNI*
Description: Terrestrial tuberous herb
Leaf terete, 10–18 cm long by 1.5–2 mm wide, base reddish, free lamina linear with subulate apex, 12–20 mm long by 2.5–3.0 mm wide, sheathing the scape at base, ending 10–15 mm below the first flower, or level with the first flower.
Inflorescence 13–21 cm tall, bearing 3–20 flowers in a dense spike 20–35 mm long. Ovary asymmetrically arcuate, 3.0–3.5 mm long. Flowers semi-erect with stiffly erect lateral sepals, c. 3.0 mm wide, dark purple. Dorsal sepal broadly ovate, truncate at base and tapered to an acuminate apex,4.0 mm long by 2.5 mm wide, concave, purplish-mauve with darker narrow bands on the margin, and three darker narrow bands along the medial and lateral veins, margins entire. Lateral sepals stiffly erect, parallel or slightly divergent, linear-lanceolate, slightly asymmetric, 5.0 mm long by 1.2mm wide, dark purplish-black, margins toward apex inrolled, apex narrowly obtuse, without a gland. Petals projecting forwards, ovate-lanceolate, 3.5 mm long by 1.2 mm wide, light purple with darker purple stripes and marginal bands, margins entire, apex long-acuminate, without a gland. Labellum hinged by a short claw, dark reddish-purple, broadly rotund-elliptic-to slightly broadly rotund-obovate, c. 3 mm long by 1.8 mm wide, broadest at middle, then tapering to an acute to short apiculate apex, margins in the distal two thirds beset with numerous, coarse spreading dark purple cilia c. 0.8 mm long, margins in the basal one third entire, callus ligulate, occupying around a third of the labellum width at the base then tapered to a rounded apex, extending three-quarters of the way to the labellum apex, dark purplish-black. Column 1.8 mm tall, 1.2 mm wide, blackish, foot ligulate, curved, 0.4 mm long; column wings shallowly divided into two unequal, closely set, lobes that hardly appear separated at all, postical lobe pinkish-mauve, ovate-lanceolate, apex acuminate, postical margins and surfaces coarsely and shortly ciliate over pigmented area; antical lobe pale, linear-oblong, symmetrical, apex irregularly obtuse, margins entire. Anther 0.9 mm long with a filiform rostrum 0.3 mm long. Pollinarium 1 mm long, pollinia c. 0.8 mm long, yellow, coarsely granular, caudicle 0.15 mm long, viscidium 0.15 mm diameter. Stigma 0.8 mm high by 0.6 mm wide, ovate-elliptic.
Flowering: Flowers: October to March, enhanced by hot summer fires (Jones 2021).
Distribution and occurrence: Victoria, ACT and New South Wales. In New South Wales known from the Southern Tablelands and Northern Tablelands, the latter in the vicinity of Mt Kaputar and Cobungra.
Genoplesium arrectum occurs as scattered, localised, populations in montane or subalpine grasslands and dry, open forests.
NSW subdivisions: NT, ST
Other Australian states: Vic.
Genoplesium arrectum can be recognised by the combination of 1) labellum margins bearing long cilia; 2) petal and dorsal sepal margins entire; 3) the absence of glands on the sepal and petal apices; 4) the dark purple coloured flowers and the stiffly erect, parallel or at best slightly divergent lateral sepals; and 5) the broadly elliptic, nearly rotund labellum. The vertical presentation of the flowers on the spike, in combination with the stiffly erect lateral sepals give the plants a distinct facie, the dense inflorescence bears dark coloured flowers that are narrow for their size relative to other members of the Genoplesium archeri group. This, in combination with the distinctive, nearly rotund, labellum shape should facilitate identification of Genoplesium arrectum.
Text by Text by Jones, D.L. in Jones, D.L. (ed.) (5 April 1991), New taxa of Australian Orchidaceae. Australian Orchid Research 2: 66, with modification by Matthew Renner, 11 July 2023.
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