Megacollybia platyphylla, also known as Broad-gilled Collybia, is a medium to large, fleshy agaric that has a pale brown, fibrillose cap, whitish gills and stem. It grows solitarily or in small groups on and near deciduous hardwood trunks, branches or woody debris. Less commonly on conifer timber.

Cap mid- to pale brown, convex to umbonate. It has radiating fibres on a dry cap surface. In dry weather, the caps of this mushroom sometimes split radially at the margins. Gills white, becoming cream colored. Reaching to the stem but not attached and they are crowded and very broad. Stem hollow at the centre and whitish, with darker fine fibrils that are less dense than on the cap. It is more or less equal and thickened at the base. It has no ring. Spore print white.

Microscopic Features: The spores are broadly ellipsoidal, smooth, have a size range of 7-10μm in length and 6-8.5μm in width and are inamyloid.

Note: Until recently, it was believed that this species could be found in certain regions of North America. However, further research has revealed that the specimens from the United States are not conspecific with Megacollybia platyphylla and have been classified as a separate species.

Megacollybia platyphylla on the www.first-nature.com web site.