The rosella spider orchid

Description

Caladenia rosella, commonly known as the rosella spider orchid is a plant in the orchid family Orchidaceae and is endemic to south-eastern Australia. It is a ground orchid with a single hairy leaf and a single scented pink flower. Although it may have had a wider distribution in the past, the total number of plants in 2000 was estimated to be 120 in four populations in Victoria. There is a single record from New South Wales but the orchid is classified as "extinct" in that state. Caladenia rosella is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, hairy leaf, 40–90 mm (2–4 in) long and 5–8 mm (0.2–0.3 in) wide. A single pale or bright pink flower 50–60 mm (2.0–2.4 in) wide is borne on a stalk 100–170 mm (4–7 in) tall. The sepals and petals have long, dark, thread-like tips covered with glandular hairs. The dorsal sepal is erect, 30–50 mm (1–2 in) long and 2–3 mm (0.08–0.1 in) wide. The lateral sepals are 30–50 mm (1–2 in) long, 4–6 mm (0.16–0.24 in) wide and spread widely, turning slightly downwards. The petals are 30–40 mm (1–2 in) long, 2–4 mm (0.08–0.2 in) wide and arranged like the lateral sepals. The labellum is 10–14 mm (0.4–0.6 in) long, 8–10 mm (0.3–0.4 in) wide and pale pink near its base but darker pink near its edges and tip. The sides of the labellum have linear teeth up to 2 mm (0.08 in) long and the tip of the labellum is curled under. There are four or six rows of pink calli along the centre of the labellum. In warm weather the flowers have a musky scent. Flowering occurs from August to September. The rosella spider orchid occurs in areas to the near-north of Melbourne where it grows in woodlands and low forests. It was formerly more widespread in central and western Victoria and in nearby parts of New South Wales.