text: mycena cinerella mycena cinerella , commonly known as the mealy bonnet , is an inedible species of mushroom in the family mycenaceae . it is found in europe and the united states , where it grows in groups on fallen leaves and needles under pine and douglas fir . the small grayish mushrooms have caps that are up to 1 . 5 cm ( 0 . 6 in ) wide atop stipes that are 5 cm ( 2 . 0 in ) long and 2 . 5 mm ( 0 . 10 in ) thick . its gills are grayish - white and adnate , with a " tooth " that runs slightly down the stipe . the fungus has both two- and four - spored basidia . as its common name suggests , it smells mealy . taxonomy first called agaricus by finnish mycologist petter karsten in 1879 , he transferred it to the genus mycena that same year . in his 1936 flora danica ( agaric flora of denmark ) jakob emanuel lange referred it to the genus omphalia ; omphalia cinerea ( p. karst . ) j.e. lange is now a synonym . mycena was named and described as a new species distinct from m. cinerella by hintikka in 1963 , who thought it to be unique due to its narrowly acute cap that lacked brownish or yellowish tones , decurrent gills , and two - spored basidia . however , intermediate forms of it have been found , and some authorities , like dutch mycena specialist maas geesteranus , believe it should be treated as a synonym of m. cinerella . the mushroom is commonly known as the " mealy bonnet " . the specific epithet cinerella means " somewhat ashy color " . description 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 . microscopic characteristics the spores are 7 – 9 by 4 – 5 μm , ellipsoid , smooth , amyloid ( reaction very weak in some collections ) . the basidia ( spore - bearing cells ) are four - spored , or occasionally a combination of two- and four - spored . the four - spored forms have clamp connections that are absent in the two - spored forms . the pleurocystidia ( cystidia found on the face of the gills ) are not differentiated . the cheilocystidia ( cystidia found on the edges of the gills ) are embedded in the hymenium and inconspicuous , measuring 22 – 36 by 5 – 11 μm . they are roughly filiform ( like thin filaments ) , with numerous contorted branches or protuberances , and club - shaped with finger - like prolongations . the flesh of the gills is homogenous , and turns vinaceous - brown when stained in iodine . the flesh of the cap has a well - differentiated pellicle , with a differentiated but not very well - developed hypoderm , and hyphae that are 10 – 20 μm wide . habitat and distribution mycena cinerella is a saprobic fungus , and derives nutrients by decomposing leaf litter and similar detritus , converting it to humus and mineralizing organic matter in the soil . the fruit bodies grow in groups on needles under pine and douglas fir , typically in the late summer and autumn . in the united states , it has been collected from michigan , washington , oregon , and california . in europe , it has also been collected from the great britain , norway , poland , and sweden .