Frankston spider-orchid

Description

Caladenia robinsonii is a terrestrial, perennial, deciduous, herb with an underground tuber. A shoot arises from the tuber each year in the early autumn producing a single hairy leaf in May. The leaf is 80–100 mm (3–4 in) long and 8–10 mm (0.3–0.4 in) wide. In September or October, one or two red and creamy-yellow flowers 30–40 mm (1–2 in) across are produced on a hairy stem 200–300 mm (8–10 in) high. The sepals, but not the petals, have thick, red glandular tips 5–10 mm (0.2–0.4 in) long. The dorsal sepal is erect near its base then gently curves forward and is 25–35 mm (0.98–1.4 in) long and 3–4 mm (0.1–0.2 in) wide. The lateral sepals are a similar size to the dorsal sepal but spread widely. The petals are 20–30 mm (0.8–1 in) long, about 3 mm (0.1 in) wide and arranged like the lateral sepals. The labellum is 12–14 mm (0.5–0.6 in) long and 7–11 mm (0.3–0.4 in) wide, and creamy yellow with a dark red tip. The sides of the labellum have many short red teeth and the tip of the labellum curves downwards. There are four or six rows of crowded, shiny red calli along the labellum mid-line. Flowering occurs in September and October