Clitocella popinalis

Description

Clitopilus popinalis (also known as Rhodocybe mundula) is fairly easily recognized by its whitish to grayish or dirty yellowish cap that develops a central depression and distinctive, more or less concentric cracks. Its gills run down the stem, and its spore print is pink. Other distinctive features include the mealy odor, the bitter taste.

It is fairly common in vegetated coastal sand-dune systems. This species occurs also across much of mainland Europe. A very similar mushroom occurs in parts of North America and it is not clear whether it is co-specific with this European species.

Mushroom Identification

1. Ecology

   Saprobic, binding leaf litter and needle duff; growing scattered or gregariously under hardwoods or conifers; summer and fall.

2. Cap

   2-5 cm; convex with an inrolled margin, becoming planoconvex, flat, or centrally depressed, with a wavy margin; dry; bald; whitish to grayish or dirty yellowish; often developing distinctive, more or less concentric wrinkles and cracks with maturity.

3. Gills

   Running down the stem; close or nearly crowded; often forked; whitish to grayish buff at first, then brownish or pinkish.

4. Stem

   3-5 cm long; up to 7 mm thick; equal, or tapering to base; bald; dry; colored like the cap; discoloring brownish basally; with copious white basal mycelium.

5. Flesh

   White; unchanging, or turning slowly gray to blackish when sliced.

6. Odor and Taste

   The odor usually mealy; taste mealy and quite bitter.

7. Chemical Reactions

   KOH on all surfaces red to brownish red.

8. Spore Print

   Pink.

9. Microscopic Features

   Spores 4-6 x 3-5 µ; irregularly ellipsoid to subamygdaliform; very finely warted (sometimes nearly invisible with light microscopy). Hymenial cystidia absent. Pileipellis a cutis of sometimes-encrusted elements 2.5-5 µ wide; reddish-brown in KOH and brownish in 10% ammonia.

10. Similar Species

    Entoloma clypeatum has a more domed cap and has much larger spores.

History

In 1821 Elias Magnus Fries described this mushroom he gave it the scientific name Agaricus popinalis. The scientific name Clitocella popinalis dates from a 2014 publication by American mycologists Kerri L. Kluting, Timothy J. Baroni and Sarah E. Bergemann, who circumscribed this new genus.

Synonyms of Clitocella popinalis include Agaricus popinalis Fr., Clitopilus popinalis (Fr.) P. Kumm., Paxillus popinalis (Fr.) Ricken., Clitocybe popinalis (Fr.) Bres., Rhodopaxillus popinalis (Fr.) Konrad & Maubl., and Rhodocybe popinalis (Fr.) Singer.

The generic name clitocella comes from ancient Latin words Clito-, meaning sloping, and -cella, meaning storage space.

The specific epithet popinalis is a Latin adjective and means 'of or belonging to an alehouse.'

Photo sources:

Photo 1 - Author: Jacob Kalichman (Pulk) (CC BY-SA 3.0)