nt
where there is limestone, though inconspicuous and easily overlooked.

2. Biatorella pruinosa (J.E. Smith) Mudd Man. Brit. Lich. 191. 1861.

_Lichen pruinosus_ J.E. Smith in Sowerby, Eng. Bot. 32: pl. 2244 1811.

Thallus light colored, usually thin and smooth, rarely disappearing;
apothecia minute to middle-sized, 0.2 to 1 mm. in diameter, adnate
scattered or crowded, flat or slightly convex, the disk pruinose, and
the exciple persistent; hypothecium lighter or darker brown; hymenium
usually pale; paraphyses coherent and becoming indistinct; asci
cylindrico-clavate; spores oblong-ellipsoid, 3 to 5 mic. long and 1 to
1.5 mic. wide.

Collected in Butler and Adams counties. On limestone. Not previously
reported from Ohio, but often occurring with the last in limestone
areas.

Lecidea Ach. Meth. Lich. XXX. 32. pl. 2. f. 1, 2. 1803.

Thallus smooth, roughened, or verrucose, in some species chinky to
areolate, or even subsquamulose, rarely rudimentary and evanescent;
apothecia minute to middle-sized, usually adnate, but rarely sessile or
immersed, with pale to black, and flat to strongly convex disk; exciple
and hypothecium from pale to dark brown in section; hymenium lighter,
most commonly pale; spores simple, hyaline, 8 in each ascus.

KEY TO THE SPECIES OF LECIDEA

Exciple soft, usually light colored.
Apothecia usually surrounded by a thalloid veil 1. L. _coarctata_
Apothecia not surrounded by a thalloid veil.
Exciple becoming covered.
Hypothecium pale or pale yellow.
Apothecia always minute.
Spores 5 to 7 mic. long 2. L. _intropallida_
Spores 7 to 15 mic. long 3. L. _varians_
Apothecia reaching middle size 4. L. _rupestris_
Hypothecium light-brown to dark brown.
Thallus gray-green or lighter 5. L. _viridescens_
Thallus darker from the first or becoming so.
Thallus minute and evanescent 6. L. _humicola_
Thallus well developed and persistent.
Thallus of raised granules 7. L. _uliginosa_
Thallus of flat granules 8. L. _sylvicola_
Exciple persistent 9. L. _flexuosa_
Exciple horny, dark colored.
Disk usually convex, commonly on wood 10. L. _enteroleuca_
Disk flat or less commonly convex, on rocks.