Slaty leek orchid

Description

Prasophyllum fuscum, commonly known as the slaty leek orchid or tawny leek orchid, is a species of orchid endemic to a small region of New South Wales. It has a single tubular green leaf and up to thirty greenish brown to reddish brown flowers. There is debate about the taxonomy of the species with some authorities considering Prasophyllum uroglossum as a separate species. Only about twenty five plants are known to survive in south-western Sydney. Prasophyllum fuscum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single tube-shaped leaf 150–400 mm (6–20 in) long and 4–6 mm (0.16–0.24 in) wide at the base. Between ten and thirty scented flowers are arranged along 70–120 mm (3–5 in) of a flowering stem 300–450 mm (10–20 in) tall. The flowers are greenish brown to reddish brown, 9–13 mm (0.4–0.5 in) long, 5–7 mm (0.2–0.3 in) wide and as with others in the genus, are inverted so that the labellum is above the column rather than below it. The dorsal sepal is egg-shaped to lance-shaped, about 9 mm (0.4 in) long, 2 mm (0.08 in) wide and pointed. The lateral sepals are linear to lance-shaped, 8–10 mm (0.3–0.4 in) long, 2 mm (0.079 in) wide and parallel to and free from each other. The petals are linear to oblong, pointed, about 7 mm (0.3 in) long, 1.5 mm (0.06 in) wide and spread widely. The labellum is linear to egg-shaped, 8–9 mm (0.3–0.4 in) long, about 5 mm (0.2 in) wide and turns upwards through about 90° near its middle. The edges of the labellum are slightly crinkled and there is a shiny, raised callus in its centre. Flowering occurs between September and December. The slaty leek orchid is only known from a single population growing on a roadside in the Wilton district. It grows in moist, sandy soil amongst grasses and sedges.