Pterostylis cardiostigma

Detailed description

Stout, terrestrial, tuberous, leafy, spring to summer-green perennial herb. Plant at flowering up to 400 mm tall. Tuber usually 1–(2), heart-shaped supporting 4–5 thick lateral roots. Stem stout, thick, dark green or pinkish-green, basal portion covered by 3–4 pink to carmine sheathing bracts; internodes short. Leaves all cauline, 5–7, sessile, usually strictly upright, uppermost overtopping galea; lamina 80–280 × 10–20 mm, dark green, linear-lanceolate, acuminate; midrib prominent, red, slightly to deeply grooved above, 2–(3) lateral yellow veins present either side, keel prominent, usually red. Flowers solitary, mostly green finely striped with white, apices usually pinkish or red, erect, tall and very narrow. Dorsal sepal up to 70 mm long, vertical in lower half, upper half steeply inclined rarely horizontal, apex acuminate, dark red. Lateral sepals overtopping galea, narrowly spreading, with long filiform, red caudae. Petals 60–65 mm long, marginal strip long and exposed, apices red; galea width at petal apex 6 mm. Labellum narrow, long, triangular, arching in upper ⅓, apex acuminate; distal half red with pale retrorse hairs on the upper surface and a dark red dorsal median ridge becoming paler near base; undersides with red median groove. Column shorter than labellum, stigma prominent, cordate, Ovary erect 10-30 mm tall.