Caladenia helvina

Caladenia helvina, commonly known as the summer spider orchid, is a plant in the orchid family Orchidaceae and is endemic to Tasmania. It is a ground orchid with a single hairy leaf and usually a single greenish-yellow to pale yellow flower with reddish teeth on the sides of the labellum and reddish calli along its mid-line.

Description
Caladenia helvina is a terrestrial, perennial, deciduous, herb with an underground tuber and a single, linear to lance-shaped, dull green, densely hairy leaf 100-160 mm long and 5-20 mm wide. Usually only a single greenish-yellow to pale yellow flower is borne on a thin, wiry, hairy spike 200-500 mm tall. The sepals and petals are linear in shape near their base but suddenly taper after about one-third of their length to a narrow, thread-like glandular tail. The dorsal sepal is 55-85 mm long, 3-4 mm wide near the base and curves forward. The lateral sepals are a similar size and shape to the dorsal sepal and the petals are slightly shorter and narrower. The labellum is egg-shaped to heart-shaped, about 15-19 mm long and 8-10 mm wide and is greenish-yellow or dull yellow. The tip of the labellum curls under and there are thin yellow or reddish-purple teeth up to 2 mm long on the sides of the labellum, and four or six rows of yellowish or purplish, golf club-shaped calli along its mid-line, decreasing in size towards the tip. Flowering occurs from December to January.

Taxonomy and naming
Caladenia helvina was first formally described by David Jones in 1991 and the description was published in Australian Orchid Research. The specific epithet (helvina) is a Latin word meaning "yellowish" or "pale yellow", referring to the colour of the flowers of this orchid.

Distribution and habitat
Summer spider orchid is widespread in Tasmania where it grows in forest in shallow, sometimes stony soil.