Entoloma decastes
Entoloma decastes is a rare species of agaric fungus in the family Entolomataceae.
It was first described in 2009 from coastal dune grassland in Sardinia, Italy, where it grows in dense clusters. The fruit bodies have a dark, translucent‑striated cap when moist, crowded gills that turn pinkish as the spores mature, and distinctive multi‑angled spores typical of the genus.
Taxonomy
Entoloma decastes was formally described by Marco Contu, Giovanni Consiglio and Machiel Noordeloos in Mycotaxon in 2009. The species epithet decastes alludes to its superficial resemblance to the unrelated cluster‑forming fungus Lyophyllum decastes. Morphological and microscopic characters place it in the subgenus Rhodopolia of the large genus Entoloma.Description
The cap measures 10–50 mm across and is thin, fleshy and convex at first, later flattening with a shallow central depression. When young and moist, the margin becomes clearly translucent and shows radial striations. The surface is glabrous, silky and dark brown with a blackish centre, often lightening slightly towards the edge. The gills are crowded, sine‑adnate or somewhat decurrent, and change from greyish to pinkish brown as the spores develop.The stipe is 10–30 mm long and 2–3 mm thick, cylindrical and hollow in maturity. Young stipes bear a white, powdery bloom at the apex and fine longitudinal fibrils below; this bloom wears off with age, leaving a smooth surface. All tissues are thin and watery, remaining unchanged when cut. The odour and taste are faintly mealy.
Microscopically, the basidiospores measure about 11–14 by 9–12 μm and are angular with 6–8 sides, a hallmark of the genus. The flesh shows abundant clamp connections and dark intracellular pigment in the cap skin.