About Pterostylis alobula (Hatch) L.B.Moore
Pterostylis alobula (Hatch) L.B.Moore is a terrestrial, perennial, deciduous herb that grows from an underground tuber. When it is not flowering, it produces a rosette of mostly egg-shaped leaves. Each leaf is 5–15 millimetres (0.2–0.6 in) long and 4–15 millimetres (0.2–0.6 in) wide, borne on a stalk up to 10 millimetres (0.4 in) long. Flowering plants typically bear a single pale green flower with white stripes, which measures 10–20 millimetres (0.4–0.8 in) in height. The flower is held on a flowering stem that can reach up to 150 millimetres (6 in) tall, and the stem bears between two and six linear to lance-shaped leaves. These stem leaves are 5–25 millimetres (0.2–1 in) long and 3–6 millimetres (0.1–0.2 in) wide. The dorsal sepal and petals of the flower are fused together, forming a hood or "galea" that covers the column, and the tip of this structure is usually held horizontally. The lateral sepals stand erect, are pressed closely against the galea, and have a broad V-shaped sinus between their bases. The labellum is red, curved, and extends above the sinus. Flowering takes place from March to October. This species, commonly called the winter greenhood, usually grows in sparse leaf litter under shrubs in forest, but it can sometimes also be found in scrub or pasture. It is found on both main islands of New Zealand and on some of New Zealand's offshore islands.
