Tricholoma roseoacerbum
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| Tricholoma roseoacerbum | |
|---|---|
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Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Agaricales |
| Family: | Tricholomataceae |
| Genus: | Tricholoma |
| Species: | T. roseoacerbum |
| Binomial name | |
| Tricholoma roseoacerbum A.Riva (1984) | |
| Synonyms[2] | |
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Tricholoma roseoacerbum is an agaric fungus of the family Tricholomataceae.[3] T. roseoacerbum is found in Europe and northeastern North America. The specific epithet roseoacerbum alludes to the rosy colouration in its cap, and overall resemblance to T. acerbum.[4]
The species was first described by the Italian mycologist Alfredo Riva in 1979 as Tricholoma pseudoimbricatum var. roseobrunneum, but that name competed with an older homonym, William Murrill's 1913 Tricholoma roseobrunneum. Riva published the species with a new replacement name in 1984.[5]
Description
Tricholoma roseoacerbum forms large, stocky mushrooms with short, thick stipes measuring 3–5 cm in height and 1.5–2.5 cm across. The caps can reach up to 12 cm in diameter, starting out rounded with inwardly curved edges when young, then becoming nearly flat with age. Young specimens have distinctive white caps marked with rust-brown streaks that resemble brush strokes. As the mushrooms mature, the cap colour darkens to whitish-brown or becomes uniformly light brown. The surface is slightly sticky to the touch in wet conditions.[6]
The gills beneath the cap are free from the stipe and white in colour. Unlike some similar species, the stipe lacks a ring or other membranous remnants. Microscopic features include colourless, smooth spores measuring 3.3–6.6 by 3–4.3 micrometre (μm), each containing one or two oil droplets. These spores show no colour reaction when tested with iodine solution (a standard test used by mycologists). The spore-producing cells, called basidia, measure about 19.8 by 26.4 μm.[6]
This species can be distinguished from the similar T. acerbum by its weakly sticky cap surface and characteristic rust-coloured streaks, and from young specimens of T. colossus by its lack of a stipe ring and smaller spores.[6]