Cap: oval then rapidly expanding, covered at first in a mass of dense, white or greyish woolly scales which break up into patches and finally leave the cap shiny, brownish grey at centre and striate and dark grey at the margin.
Stem: white, covered particularly towards the base with white, woolly scales, long, fragile, tapering upwards and at the base often elongated into a ‘tap root’ buried in the dung.
Gills: free, white but then rapidly dissolving into a black liquid.
Flesh: thin and whitish.
Spore-print: violaceous black.
Spores: medium sized, ellipsoid, smooth with a distinct germ-pore and 10-12 × 5-6 µm in size.
Facial cystidia: absent.
Marginal cystidia: inflated and large.
General Information: It is found on manure heaps, on straw dung and on silage heaps: very common throughout the year.
C. macrocephalus (Berkeley) Berkeley is very closely related to C. cinereus, but differs in having much larger spores over 12-15 × 7-9 µm, a long cap and a stem which lacks a rooting base.