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..
In Leptonia the stem is cartilaginous, hollow or stuffed, smooth and somewhat shining. The pileus is thin, umbilicate or with the center darker, the surface hairy or scaly, and the margin at first incurved. The gills are adnate or adnexed at first, and easily separating from the stem in age. Many of the species are bright colored.
This species occurs on the ground in woods or in open grassy places. The plants are 3-5 cm. high, the cap 2-4 cm. broad, and the stem 2-3 mm. in thickness.
The pileus is convex, then more or less expanded, umbilicate, rarely umbonate, hair brown (mouse colored), with dark scales on the center and minute scales over the surface, striate.
The gills are sinuate to adnexed. The spores are strongly 5-6 angled, 10-12x8-10 µ. The stem is smooth, even, usually the same color as the cap, but sometimes it is reddish brown, green, or blue. Figure 142 is from plants (No. 3996, C. U. herbarium) collected at Blowing Rock, N. C, during September, 1899.
Leptonia incana Fr., is a more common species, and is characterized by an odor of mice.
Leptonia asprella. Cap hair brown (mouse colored), minute dark scales at center, stem same color, but sometimes reddish brown, green or blue, gills flesh color.