Inocybe pusio

Description

Inocybe pusio is one of a small number of inocybes in which the stipes are lilac, at least in part (and then at the apex). This color can fade quickly, so having young fruit bodies is essential for correct identification. The cap is relatively dark brown and coarsely fibrillose to somewhat scaly. Gills are light gray to slightly lilac-tinged when young, and become darker brown with age. The stipe is fibrillose, lilac when young (at least the upper part), brownish in the lower part with age, and the upper part powdery and often remaining whitish.

This mushroom occurs under broad-leaf trees, in summer and autumn. It almost certainly contains the dangerous poison muscarine, and so it must be avoided at all costs when gathering fungi to eat.

Mushroom Identification

1. Cap

   The brown cap of Inocybe pusio has a diameter of 1 to 3.5cm. sharply conical at first, it gradually flattens often retaining a smooth or very finely tomentose central umbo. The outer region is rimulose (breaking into streaky brown radial fibers, progressively paler towards the margin and tending to split its flesh radially towards the edge of the cap). Beneath the cuticle, the flesh is white, unchanging on exposure to air.

2. Gills

   The moderately crowded, adnexed or adnate gills start off creamy-gray with a violaceous tinge, and they turn browner as the spores mature.

3. Cheilocystidia

   Gill-edge cystidia are cylindrical to fusiform or langeniform, thin-walled, 40-75 x 10-15µm. encrusted with apical cystals.

4. Spores

   Ellipsoidal to subamygdaliform with a pointed apex, smooth 8-11 x 4.5-6µm.

5. Spore Print

   Dull brown.

6. Stem

   3 to 6mm in diameter and 2 to 5cm tall, the stem is pruinose and silky, violaceous to gray-violaceous towards the apex; it is smoother and whitish below. The base is slightly swollen, and there is no stem ring.

7. Caulocystidia

   Stem surface cystidia are present in the upper third of the stem, and in form and dimensions they are similar to the cheilocystidia.

8. Odor and Taste

   Slightly spermatic smell. Reported to have a mild taste.

History

In 1889 Finish mycologist Petter Adolf Karsten described this mushroom scientifically, giving it the name Inocybe pusio, by which it is generally known today.

Synonyms of Inocybe pusio include Inocybe obscura var. obscurissima R. Heim.

Inocybe, the genus name, means 'fibrous head', while the specific epithet pusio is a Latin noun meaning 'little boy'.

Photo sources:

Photo 1 - Author: drifting_biospheres (CC BY-NC 4.0)

Photo 2 - Author: fmr (Attribution-NoDerivatives 4.0 International)