Frog greenhood (Pterostylis sargentii)

Description

Pterostylis sargentii, is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of between three and six leaves 5–18 mm (0.2–0.7 in) long and 3–8 mm (0.1–0.3 in) wide on a short stalk. Flowering plants lack a rosette but have between three and ten stem leaves which are 8–30 mm (0.3–1 in) long and 2–4 mm (0.08–0.2 in) wide on the flowering stem. Up to six white and green or brown striped flowers are borne on the flowering stem which is 50–200 mm (2–8 in) high. The flowers are 15–25 mm (0.6–1 in) long and 5–7 mm (0.2–0.3 in) wide. The dorsal sepal and petals form a hood or "galea" over the column with the dorsal sepal having a thread-like tip 2–3 mm (0.08–0.1 in) long. The lateral sepals turn downwards are joined for about half their length, then suddenly taper to narrow tips 4–6 mm (0.16–0.24 in) long. The labellum is 4–5 mm (0.16–0.20 in) long, about 2 mm (0.08 in) wide, dark brown with three lobes, the side ones with a large, horn-like appendage. Flowering occurs from July to October.Pterostylis sargentii, is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of between three and six leaves 5–18 mm (0.2–0.7 in) long and 3–8 mm (0.1–0.3 in) wide on a short stalk. Flowering plants lack a rosette but have between three and ten stem leaves which are 8–30 mm (0.3–1 in) long and 2–4 mm (0.08–0.2 in) wide on the flowering stem. Up to six white and green or brown striped flowers are borne on the flowering stem which is 50–200 mm (2–8 in) high. The flowers are 15–25 mm (0.6–1 in) long and 5–7 mm (0.2–0.3 in) wide. The dorsal sepal and petals form a hood or "galea" over the column with the dorsal sepal having a thread-like tip 2–3 mm (0.08–0.1 in) long. The lateral sepals turn downwards are joined for about half their length, then suddenly taper to narrow tips 4–6 mm (0.16–0.24 in) long. The labellum is 4–5 mm (0.16–0.20 in) long, about 2 mm (0.08 in) wide, dark brown with three lobes, the side ones with a large, horn-like appendage. Flowering occurs from July to October.