This section is from the book "Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc.", by George Francis Atkinson. Also available from Amazon: Studies of American Fungi: Mushrooms, Edible, Poisonous, Etc..
Abbreviations : cm. = centimeter (about 2 1/2 cm. make one inch).
mm.= millimeter (about 25 mm. make 1 inch).
µ = one micron (1000 µ= 1 mm.). Adnate, said of the gills when they are attached squarely, or broadly, to the stem. Adnexed, said of gills when they are attached only slightly or only by the upper angle of the stem. Anastomose, running together in a net-like manner.
Annulus, the ring or collar around the stem formed from the inner or partial veil. Appendiculate, said of the veil when it clings in fragments to the margin of the pileus. Arachnoid, said of the veil when it is cobwebby, that is, formed of loose threads. Ascus, the club-shaped body which bears the spores inside (characteristic of the Ascomycetes). Basidium (pl. basidia) the club-shaped body which bears the spores in the Basidiomycetes. These stand parallel, and together make up the entire or large part of the hymenium or fruiting surface which covers the gills, etc. Paraphyses (sterile cells) and sometimes cystidia (longer sterile cells) or spines are intermingled with the basidia. Bulbous, said of the enlarged lower end of the stem in some mushrooms. Circumscissile, splitting transversely across the middle, used to indicate one of the ways in which the volva ruptures.
Cortina, a cobwebby veil.
Cuticle, the skin-like layer on the outside of the pileus.
Decurrent, said of the gills when they extend downward on the stem.
Diffluent, said of the gills when they dissolve into a fluid.
Dimidiate, halved, said of a sessile pileus semi-circular in form and attached by the plane edge directly to the wood.
Echinulate, term applied to minute spinous processes, on the spores for example.
Eccentric, said of a stem when it is attached to some other point than the center of the pileus.
Fimbriate, in the form of a delicate fringe.
Fistulose, becoming hollow.
Floccose, term applied to indicate delicate and soft threads, cottony extensions from the surface of any part of the mushroom.
Flocculose, minutely floccose.
Fuliginous (or fuligineous), dark brown, sooty or smoky.
Fulvous, tawny, reddish yellow.
Fusoid, like a spindle.
Furfuraceous, with numerous minute scales.
Gleba, the chambered tissue forming the hymenium (fruiting surface) in the puff-balls and their allies.
Hygrophanous, appearing to be water soaked.
Hymenium, the fruiting surface of the mushrooms and other fungi.