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 inconspicuous
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 pl. 28. f. 2. 1794.

Thallus thin and smooth or thicker and roughened, sometimes subareolate,
ash-white to green-gray and darkening, rarely disappearing; apothecia