About Pterostylis australis Hook.f.
Pterostylis australis Hook.f. is a terrestrial, perennial, deciduous herb that grows from an underground tuber. Between three and six leaves grow along its flowering stem. The leaves are 40–150 mm (2–6 in) long and 10–15 mm (0.4–0.6 in) wide; they are elliptic near the stem base, becoming lance-shaped near the stem apex. The flowering stem is 100–250 mm (4–10 in) tall, and none of the leaves extend above the single, green flower with white stripes. The dorsal sepal and petals are fused to form a hood (called a "galea") that covers the column. The dorsal sepal has a long-tapering, down-curved tip. The two lateral sepals curve backward, away from each other. The labellum is curved, dark green, reddish near its tip, and has an arched ridge along its midline. Flowering takes place from November to January. This greenhood orchid grows in scrub and tall forest, especially forest dominated by Nothofagus. It can be found on the North Island, South Island, and Stewart Island of New Zealand. On the North Island, it only grows south of near East Cape, and only on higher mountain peaks.
