Thallus adnate at the center with ascendant margins of the lobes, 6 to 11 cm. in diameter, the upper surface smooth and shining, devoid of trichomatic hyphae, the lobes broad with crisped, crenate margins, except those bearing the apothecia, these much narrower and more elongated and usually digitately clustered, brown in color for the most part, the lower surface showing through a reticulation of dark veins as small light-colored spots, numerous dark rhizoids extending downward from the veins; medulla of densely interwoven and irregularly disposed hyphae; apothecia orbicular, and usually revolute, the disk dark brown, 3 to 10 mm. in diameter; hypothecium pale brown; hymenium pale below and dark brown above; asci clavate to cylindrico-clavate; spores acicular, straight or slightly curved, 4- to 6-celled, 42 to 70 mic. long and 3 to 4 mic. wide. Examined from Clark, Fairfield, and Morgan counties. On earth. Rare in Ohio. 7. Peltigera horizontalis (L.) Hoffm. Deutsch. Fl. 2: 107. 1795. _Lichen horizontalis_ L. Mant. Pl. 2: 132. 1771. Thallus mostly adnate, the margins scarcely ascending, 6 to 20 cm. in diameter, the upper surface smooth and shining, devoid of trichomatic hyphae, green-gray to brown, the lobes broad and rounded with entire or crenate margins, the lower surface covered with numerous veins, these giving a dark coloration toward the center and becoming light colored toward the margins, numerous dark rhizoids extending down from the veins; medulla of thick-walled, densely and irregularly disposed hyphae; apothecia on somewhat narrowed lobes, transversely oblong or infrequently orbicular, the disk red-brown, concave, 2 to 4 mm. in diameter; hypothecium light brown; hymenium pale below and dark brown toward the upper surface; asci cylindrico-clavate; spores fusiform to long-ellipsoid, straight to curved, 4-celled, 26 to 40 mic. long and 5 to 6.5 mic. wide. (Fig. 8 a). Examined from Lake and Fairfield counties. On earth and mossy rocks. Rare in Ohio. Nephroma Ach. Lich. Univ. 101. 521. pl. 11. f. 1. 1810. Thallus foliose, but smaller and thinner than that of _Peltigera_, and devoid of trichomatic hyphae, more or less closely attached to the substratum by rhizoids; cortex well developed on both upper and lower sides; medulla well developed (Fig. 2); apothecia confined to the lower side of the thallus, marginal on narrow, slightly elongated lobes, thalloid margin persistent and crenate; hypothecium usually some shade of brown; hymenium usually pale below and brown above; paraphyses simple or branched; spores brown, 4-celled, 8 in each ascus. The algal-host cells occur as in _Peltigera_. 1. Nephroma helvetica Ach. Lich. Univ. 523. 1810.