chomatic hyphae.
Apothecia orbicular and revolute, spores 4- to
8-celled 6. P. polydactyla
Apothecia usually transversely oblong, spores
4-celled 7. P. horizontalis

1. Peltigera aphthosa (L.) Willd. Fl. Berol. Prodr. 347. 1787.

_Lichen aphthosus_ L. Sp. Pl. 1148. 1753.

Thallus closely attached to the substratum at the center, the lobes
ascending, 6 to 8 cm. in diameter, smooth and devoid of trichomatic
hyphae above, cephalodia more or less rounded and irregularly scattered
over the surface (Fig. 3), the lobes broad and rounded with crenate
margins, brown above, the lower surface having numerous veins, these
forming a dark brown nap at the center, the veins distinct and light
toward the margin, dark rhizoids extending from the veins; medulla
composed of thick-walled, densely interwoven hyphae, irregularly
disposed; apothecia on extended lobules, orbicular and frequently
revolute, the disk red-brown, 2 to 5 mm. in diameter, the margin entire
or crenulate; hypothecium pale brown; hymenium hyaline to pale brown
above; asci cylindrico-clavate; spores acicular, straight, 4- to
6-celled, 47 to 66 mic. long and 4 to 5 mic. wide (Fig. 8, d).

Examined from Clark County. Also reported from Champaign County. On
earth and often on humus-covered rocks. Rare in Ohio.

2. Peltigera praetextata (Sommerf.) Fink. Proc. Ind. Acad. Sci. 1918:
267. 1918.

_Peltigera ulorrhiza praetextata_ Sommerf. Lapp. Suppl. 123. 1826.

Thallus adnate toward the center, more or less ascending toward the
margins, 7 to 15 cm. in diameter, the upper surface having isidioid
branchlets or lobules scattered more or less thickly, the lobes broad,
wavy, crenate, with frequently isidioid, lobulate margins, trichomatic
hyphae often present, usually green-gray toward the center, becoming
brown toward the margin, the lower surface light with numerous dark
veins and bearing rhizoids of the same color, the veins and rhizoids
becoming light colored toward the margin; medulla of densely interwoven
and irregularly disposed hyphae; apothecia on narrow, somewhat extended
lobes, the disk brown to brown-black, revolute, 2 to 5 mm. in diameter,
hypothecium light to darker brown; hymenium pale below and brown above;
asci cylindrico-clavate; spores sub-fusiform to acicular, usually
straight but sometimes slightly curved, 4- to 6-celled, 42 to 56 mic.
long and 3 t