Plumose, feathery.
Pore, orifice of the tubes of polypores.
Poriform, in the form of pores.
Porous, having pores.
Powdery, covered with bloom or powder.
Projecting, the anterior end jutting out beyond the margin.
Proliferous, applied to an organ which gives rise to secondary ones of the same kind.
Pruinose, covered with frost-like bloom.
Pruniform, plum-shaped.
Pubescent, downy.
Pulverulent, covered with dust.
Pulvinate, cushion-shaped.
Punctate, dotted with points.
Pyriform, pear-shaped.
Quaternate, arranged in groups of four.
Receptacle, a part of the mushroom extremely varied in form, consistency, and size, inclosing the organs of reproduction.
Remote, when the margin of the gill comes to an end before reaching the stem.
Reniform, kidney-shaped.
Repand, bent backwards.
Resupinate, of mushrooms spread over the matrix without any stem and with the hymenium upwards; inverted by twisting of the stalk.
Reticulate, marked with cross lines like the meshes of a net.
Revolute, rolled backwards; of the margin of a cap, the opposite of involute.
Rhodospore, rose or pink spore.
Rimose, cracked.
Ring, a part of the veil adhering to the stem of a mushroom in the shape of a ring.
Rivulose, marked with lines like rivulets.
Rubiginous, rust colored.
Rufescent, reddish in color.
Student's Hand-Book of Mushrooms of America, Edible and Poisonous · The Wunder Library — complete classics, free to read, with narration.