Pterostylis oliveri

Detailed description

Terrestrial, tuberous, glabrous, spring to summer-green perennial herb, mostly solitary or forming small patches of 3–5 plants through vegetative extension. Plant at flowering 100–380 mm tall. Stem more or less erect to decumbent, smooth, yellow green to green, internodes mostly shorter than leaves, sometimes very short near base. Leaves 4–6, spreading, margins entire, size changing from base to top of stem; lamina of lower leaves 50–100 × 20–30 mm, oval to broadly elliptic or narrowly obovate, apex obtuse, narrowing to a broadly winged, mostly short petiole; upper leaves progressively more acute, the uppermost little shorter but sessile, ovate, sometimes almost acuminate, often reaching but scarcely overtopping the galea. Flower solitary, erect, front mostly dark green finely striped with white, stripes of white widening toward back of galea with green narrowing. Ovary erect. Dorsal sepal 30–50 mm tall, slightly to distinctly inclined in its proximal portion, apex long, narrow, more or less parallel-sided with only weakly involute margins, strongly deflexed; lateral sepals diverging at a narrow angle, caudae of lobes greatly attenuated erect, sometimes strongly deflexed to the back of the galea. Petals much shorter than dorsal sepal with acute apices. Labellum narrowly triangular, slightly arched protruding. Column shorter than labellum; stigma narrowly ellipsoid, scarcely distinguished from column and rather flat.