Revolute, rolled backward.
Rugose, wrinkled.
Rugulose, with minute wrinkles.
Saprophytic, growing on dead organic matter.
Sessile, where the pileus is attached directly to the matrix without any stem.
Sinuate, said of the gills when they are notched at their junction with the stem.
Stipe, the stem.
Sulcate, furrowed.
Squamulose, with minute scales.
Squarrose, with prominent reflexed scales.