Pterostylis maxima

Pterostylis maxima, commonly known as the large rustyhood, is a plant in the orchid family Orchidaceae and is endemic to south-eastern Australia. It has a rosette of leaves at its base and up to eight relatively large, dark brown flowers with transparent "windows" and a thin, dark insect-like labellum.

Description
Pterostylis maxima, is a terrestrial, perennial, deciduous, herb with an underground tuber. It has a rosette of between six and twelve egg-shaped leaves at the base of the flowering spike, each leaf 15-45 mm long and 10-18 mm wide. Between two and eight dark reddish-brown flowers with transparent sections, each flower 35-60 mm long and 12-14 mm wide are borne on a flowering spike 200-350 mm tall. Four to six stem leaves are wrapped around the flowering spike. The dorsal sepal and petals are joined to form a hood called the "galea" over the column with the dorsal sepal having a thread-like tip 7-12 mm long. The lateral sepals are wider than the galea, dished, densely hairy on their outer edges and suddenly taper to thread-like tips 25-35 mm long and parallel to each other. The labellum is reddish-brown, thin and insect-like, 6-8 mm long and about 4 mm wide. The "head" end is swollen with two long bristles and there are up to 8 to 12 shorter bristles on each side of the "body". Flowering occurs from October to November.

Taxonomy and naming
Pterostylis maxima was first formally described in 1989 by David Jones and Mark Clements from a specimen collected near Bendigo and the description was published in Australian Orchid Research. The specific epithet (maxima) is a Latin word meaning "greatest" or "largest".

Distribution and habitat
The large rustyhood occurs in scattered populations south from Temora in New South Wales and across Victoria to the south-east bioregion of South Australia. It grows in woodland, open forest and mallee.

Conservation
Pterostylis maxima is described as "vulnerable" in Victoria and as "endangered" in South Australia.