336 
OHIO BIOLOGICAL SURVEY 
Systematic Account. 
LECIDEACEAE 
Thallus crustose, without plectenchymatous cortex (Fig. 2, a), vary¬ 
ing from granulose and often evanescent to conspicuous, areolate, or even 
subsquamulose conditions, attached to the substratum by hyphal rhizoids 
(Fig. 2, d), and in a few instances extending up as a veil and surrounding 
the apothecia laterally, the hyphae densely interwoven toward the upper 
surface, but more loosely disposed below (Fig. 2, a and b); apothecia usu¬ 
ally minute or small, commonly rounded, the exciple weak and obscure 
(Fig. 10, d), or more strongly developed when conspicuous and much darker 
in color (Fig. 11, b); hypothecium varying from hyaline to dark brown 
(Fig. 10, band Fig. 11, c); hymenium almost always lighter and commonly 
hyaline (Figs. 10 and 11, a); paraphyses usually simple, but branched forms 
to be found frequently (Figs. 1 and 12), pale throughout or darkened 
toward the sometimes enlarged apex, commonly more or less coherent and 
indistinct at maturity; spores simple and hyaline to muriform and brown 
(Figs. 2, 3, 4, 5, 6, 7, 8, 9, and 13). 
KEY TO THE GENERA 
Spores minute, numerous in each ascus .. . . Biatorella, p. 
Spores larger, usually 8 in each ascus, 
Spores hyaline. 
Spores one-celled (simple) . Lecidea, p. 
Spores more than one-celled (compound). 
Spores 2-celled. Biatorina, p. 
Spores 4- to several-celled. 
Spores ellipsoid, fusiform, or dactyloid. Bilimbia, p. 
Spores acicular . Bacidia, p. 
Spores brown, or becoming brown. 
Spores 2-celled. Buellia, p. 
Spores 4-celled and becoming muriform. Rhizocarpon, p. 
Biatorella De Not. Giorn. Bot. Ital. 21. 192. 1846. 
Thallus granulose to verrucose and subareolate, sometimes inconspicu¬ 
ous and evanescent; apothecia minute to middle-sized, adnate or more or 
less immersed, exciple usually prominent and persistent, but sometimes 
becoming covered, disk flat to convex; hypothecium and hymenium pale 
to brown; spores simple, hyaline, minute, numerous in each ascus. 
KEY TO THE SPECIES OF BIATORELLA 
The whole apothecium dark colored.1. B. simplex 
The disk of the apothecium white-pruinose...2. B. pruinosa 
1 Biatorella simplex (Dav.) Br. & Rostr. Bot. Tidssk. 3: 241 1869. 
Lichen simplex Dav. Trans. Linn. Soc. Lond. 2: 283. pi. 28. f. 2. 1794. 
Thallus thin and smooth or thicker and roughened, sometimes subar¬ 
eolate, ash-white to green-gray and darkening, rarely disappearing; apothecia 
minute to middle-sized, 0.2 to 0.8 mm. in diameter, adnate, scattered or 
