=A. faba´ceus= Berk.—relating to beans. =Pileus= 4–5 in. across, thin, almost submembranaceous, umbonate, conical when young, becoming nearly plane as it expands, white, viscid when moist; epidermis smooth, tough, feeling like fine kid leather, turning yellow when bruised. =Stem= 3–4 in. high, ⅓ in. thick, white, smooth, with the exception of a few fibrilla, equal except at the base. =Veil= large, at first covering the gills and connecting the margin with the stem, white, externally floccose. =Gills= crowded, very thin, not ventricose, free, brown when young, then darker brown, at length almost black like the dark part of a bean flower. A fine species allied to A. arvensis. When young it has a peculiar but not unpleasant smell. On the ground, amongst dead leaves in open woods. Waynesville, September 10, 1844. Hooker’s London Jour. of Botany, 1847. Described by Berkeley from specimens collected by Thomas G. Lea, in the vicinity of Cincinnati. On ground among old leaves in woods. Common. =Pileus= 3–4 in. broad. =Stem= 3–4 in. high. =Spores= brown, nucleate on one side, small, 5.5µ long. _Morgan._ This is among the most delicious species for the table. Fresh specimens have a distinct taste and odor of peach kernels or bitter almonds which is nearly lost in cooking. Am. Jour. Science and Arts, 1850. _Curtis._ Ohio, _Lea_, _Morgan_; North Carolina, _Curtis_; South Carolina, _Ravenel_; Massachusetts, _Sprague_. *** _Gills at first whitish._ =A. arven´sis= Schaeff.—belonging to cultivated ground. HORSE MUSHROOM, PLOWED-LAND MUSHROOM. (A. Georgii Sow., A. pratensis Scop., A. edulis Krombh., A. exquisitus Vitt.) =Pileus= at first convex or conical, bell-shaped then expanded, at first more or less floccose or mealy, then smooth white or yellowish. =Flesh= white. =Gills= close, free, generally broader toward stem, _at first whitish, then pinkish_, finally blackish-brown. =Stem= equal or slightly thickened toward the base, smooth, _hollow or stuffed_ with a floccose pith; ring rather large, thick, the lower or exterior surface often cracked in a radiate manner. =Plant= 2–5 in. high. =Pileus= 3–5 in. or more broad. =Stem= 4–10 lines thick. Cultivated fields and pastures. Summer and autumn. This species is so closely related to the common mushroom that it is regarded by some authors as a mere variety of it. Even the renowned Persoon is said to have written concerning it: “It appears to be only a variety of A. campestris.” Fries also says that it is commonly not distinguished from A. campestris, but that it is diverse in some respects; its white flesh being unchangeable, its gills never deliquescing, remaining a long time pale and not becoming dark-red in middle age. Berkeley says of it: “A coarse but wholesome species, often turning yellow when bruised.” _Peck_, 36th Rep. N.Y. State Bot. =Spores= spheroid-elliptical, 9×6µ _K._; 11×6µ _W.G.S._; elliptical, 8–10×5–6.5µ _Peck_.