Megacollybia platyphylla

What You Should Know

Megacollybia platyphylla is a medium to large, fleshy agaric that has a pale brown, fibrillose cap, whitish gills and stem. It grows on buried decidous branches and stumps.

With a dark cap covering pallid gills, this is another tricky species to identify in situ, but its identity is at once betrayed if you excavate the base of the stem.

Synonyms: Megacollybia platyphylla (Pers.) Kotl. & Pouzar, Tricholomopsis platyphylla (Pers.) Singer, Collybia platyphylla (Pers.) P. Kumm.

Other names: Broad Gill, Platterful Mushroom.

Megacollybia platyphylla Mushroom Identification

1. Ecology and Habitat

   Saprobic; solitary to several on and near deciduous logs, stumps, wood debris, or on the ground from buried wood; May through October.

2. Cap

   Caps 5-12.5 cm wide and stipes 7.5-12.5 cm long and 1-2 cm thick. Smooth; brownish-gray caps; radially streaked with dark fibers.

3. Gills

   Attached; white; broad; edges uneven to ragged, appearing eroded.

4. Spore print

   White.

5. Stipe

   White, smooth, often with white rhizomorphs present at the base.

Megacollybia platyphylla Taxonomy and Etymology

This saprobic fungus was described scientifically in 1796 by Christiaan Hendrik Persoon, who established its basionym when he gave it the binomial scientific name Agaricus platyphyllus.

In 1972 Czech mycologists František Kotlaba and Zdeněk Pouzar reclassified this species as Megacollybia platyphylla, which is its currently accepted scientific name.

Synonyms of Megacollybia platyphylla include Agaricus grammocephalus Bull., Agaricus platyphyllus Pers., Agaricus repens Fr., Collybia platyphylla (Pers.) P. Kumm., Collybia grammocephala (Bull.) Quél., Agaricus tenuiceps Cooke & Massee, Tricholoma tenuiceps (Cooke & Massee) Massee, Tricholomopsis platyphylla (Pers.) Singer, and Oudemansiella platyphylla (Pers.) M.M. Moser.

The genus name Megacollybia come from Mega- meaning large, and -collybia meaning coins or coin-shaped, and so by implication, these are larger than the coin-shaped fungi found in the genus Collybia.

Incidentally, several of the more common species that were for many years comfortably settled in the Collybia genus have recently been transferred to the genera Gymnopus and Rhodocollybia.

The specific epithet platyphylla comes from platy- meaning wide and -phylla meaning leaves (or gills in this case).

Sources:

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