Pterostylis dolichochila, commonly known as the long-tongued shell orchid, is a species of orchid endemic to southern Australia. As with similar orchids, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves but the flowering plants have a single flower with leaves on the flowering spike. This greenhood has a green and white flower with reddish-brown stripes and a sharply pointed dorsal sepal.
Pterostylis dolichochila is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of four to ten egg-shaped leaves. Each leaf is 4–12 mm long and 3–8 mm wide. Flowering plants have a single flower 20–25 mm long and 7–9 mm wide borne on a spike 50–150 mm high with three or four stem leaves wrapped around it. The flowers are green and white with reddish-brown stripes. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal curves forward with sharp point or a thread-like tip 1–2 mm long. The lateral sepals are held closely against the galea, have an erect, thread-like tip 15–20 mm long and a broad, flat sinus between their bases. The labellum is 13–15 mm long, about 4 mm wide, brown, blunt, and curved and protrudes above the sinus. Flowering occurs from April to August.[1] [2] [3]
Pterostylis dolichochila was first formally described in 1985 by David Jones and Mark Clements and the description was published in the fourth edition of Flora of South Australia.[4] The specific epithet (dolichochila) is derived from the Ancient Greek words dolichos meaning "long"[5] and cheilos meaning "lip".
The long-tongued shell orchid grows on calcareous sand and limestone, sometimes forming large colonies, in mallee in the south-east of South Australia and the Little Desert and Big Desert areas of Victoria.