 The cap of M. cinerella is white and small , with a diameter typically ranging from 0 @.@ 5 to 1 @.@ 5 cm ( 0 @.@ 2 to 0 @.@ 6 in ) . Initially hemispherical , obtusely conic , and then convex , it expands during maturity , developing visible grooves on the surface that correspond to the gills underneath the cap . The cap has a broad , flattened umbo . The cap surface is smooth and moist , with a slimy margin that is initially pressed against the stipe ; with age the margin becomes notched and sometimes scalloped , turning translucent . The cap color is dark gray to pale gray , somewhat hygrophanous , fading to ashy white or brown when dry . The flesh is thin , gray , cartilaginous and tough , with a strongly farinaceous ( mealy , similar to raw potatoes ) odor and taste if crushed or chewed . The whitish to grayish gills are moderately broad ( 2 – 3 mm ) with a spacing that is close to subdistant , and 18 – 26 reach the stipe , interspersed with two or three tiers of lamellae ( short gills that do not extend fully from the cap margin to the stipe ) . The stipe attachment is adnate or arcuate , but later develops a pronounced decurrent tooth . The decurrent tooth occasionally separates from the stipe and forms a collar around it . The stipe is 2 – 5 cm ( 0 @.@ 8 – 2 @.@ 0 in ) long , 1 – 2 @.@ 5 mm ( 0 @.@ 04 – 0 @.@ 10 in ) thick , equal in width throughout , hollow , cartilaginous , and brittle . The stipe surface is smooth or polished , with the apex initially faintly pruinose ( as if covered with a fine whitish powder ) . The base of the stipe is sparsely covered with sharp , straight , stiff hairs , and is the same color as the cap or paler . The mushroom is inedible . 
