About Pterostylis grandiflora R.Br.
Pterostylis grandiflora, commonly called cobra greenhood or superb greenhood, is a terrestrial, perennial, deciduous herb that grows from an underground tuber. When it is not flowering, it produces a rosette of four to nine egg-shaped leaves. Each leaf is between 4 and 20 millimetres long and 3 to 10 millimetres wide. Flowering plants produce a single flower that is 27 to 35 millimetres long and 17 to 23 millimetres wide. The flower is held on a stalk 150 millimetres high, with four to nine stem leaves wrapped around the stalk. The flowers are white, marked with green and deep red-brown stripes and spots. The dorsal sepal and petals are fused together to form a hood, called a "galea", that covers the column. The dorsal sepal curves forward and ends in a thread-like tip 3 to 5 millimetres long. The lateral sepals are held erect, pressed closely against the galea, with a broad, flat, platform-like protruding gap between their bases. The labellum is 17 to 20 millimetres long, about 3 millimetres wide, reddish-brown, and protrudes above the gap between the lateral sepals. Flowering takes place from May to August. This orchid grows in moist shady spots in forest on the coast and tablelands of southern Queensland, New South Wales, Victoria and Tasmania. In horticulture, Pterostylis grandiflora is easier to grow than many other greenhood orchids, but it is mostly cultivated only by orchid enthusiasts. To grow successfully, it must be kept dry during its dormant stage, and kept moist in 50% sunlight during its growth and flowering stage.
