 The fruit body is a medium @-@ sized mushroom , with a cap 6 – 10 cm ( 2 @.@ 5 – 4 in ) in diameter , though larger specimens occasionally reach 15 cm ( 6 in ) . The cap is initially hemispherical before flattening with maturity , and has a broad , shallow umbo . The cap margin is initially curled inwards but uncurls as it matures . The cap surface is silvery @-@ grey and covered with concentrically patterned darker scales of a grey , brown or blackish colour that grow paler toward the cap margin , Secretan noting its resemblance to the cap of Sarcodon imbricatus . The gills are free ( unattached to the stalk ) , white and thick , may have a yellow or greenish tint , and may drip water , as may the top of the stalk when broken . With age , the gill edges can become jagged and rough . The gill spacing is rather variable , ranging from distant to crowded ; typically , between 100 – 120 gills extend fully from the stalk to the edge of the cap , with a variable number of lamellulae ( shorter gills not extending fully from stalk to cap margin ) . 
