Cortinarius rotundisporus, also known as the elegant blue webcap, is a basidiomycete mushroom of the genus Cortinarius found in southern Australia, where it is found in eucalypt forests and rainforests. The cap of the fruit body is a steely blue colour, with a yellowish boss, and paler similarly coloured stipe.
Cortinarius rotundisporus was initially described by naturalists John Burton Cleland and Edwin Cheel in 1918. It is a member of the subgenus Myxacium within the genus Cortinarius; these species are characterized by the presence of a viscid to glutinous outer veil and stipe. Its specific name is derived from the Latin rotundus "round", and Ancient Greek spora "seed".[1]
The cap ranges from 2.5 to 7 cm (1–3 in) in diameter, and is initially convex before flattening. It has a slight boss that is mustard-, honey- or cream-yellow tinged and steely blue elsewhere. The adnate gills are creamy or lilac-tinged early, and darken with the spores. The slender 5–7.5 cm (2–3 in) stipe lacks a ring; it is pale yellow or white with a tinge of the cap colour. The flesh is yellowish and may have a lilac or pale blue tinge. The spore print is reddish brown and the oval to round spores measure 8.5 × 6.5 μm.[1] [2] There is no particular taste or smell. Potassium hydroxide will produce a pink-purple reaction in the stipe or cap.[3] The mycelium is white.[3]
It has been found in New South Wales, Victoria, southeastern South Australia, southern Western Australia, and Tasmania.[1] [4] It has also been recorded from New Zealand.[5]
Fruit bodies are found in eucalypt forests and rainforests,[2] and occasionally cleared areas.[6] It forms associations with Eucalyptus, Leptospermum and possibly Casuarina.[5]