4. Biatorina chalybeia (Borr.) Mudd, Man. Brit. Lich. 180. 1861.
Lecidea chalybeia Borr. in Sowerby, Eng. Bot. Suppl. 1: pl. 2687. f. 2. 1831.
Thallus a thin, smooth or roughened, ash-gray and darkening crust, forming a continuous layer, becoming inconspicuous and rarely disappearing; apothecia minute to small, 0.3 to 0.5 mm. in diameter, adnate to sessile, concave to slightly convex, black, the exciple concolorous, prominent, and rarely becoming covered; hypothecium dark brown; hymenium pale below and pale brown above; paraphyses wide and strong, distinct to coherent-indistinct; asci clavate; spores oblong-ellipsoid, 8 to 12 mic. long and 3.5 to 4.75 mic. wide ([Fig. 4]).
Collected in Butler County. On calcareous rocks. Not previously reported from Ohio, and probably rare in the State.
The spores are somewhat larger than in European specimens.
Bilimbia De Not. Giorn. Bot. Ital. 21: 190. 1846.
Thallus usually composed of minute granules, these often run together to form a leprose or verrucose and rarely areolate or even subsquamulose crust, rarely disappearing; apothecia minute or small, usually adnate, with a weak and often covered exciple; hypothecium pale to dark brown; hymenium pale or tinged brown; spores hyaline, usually fusiform or dactyloid, varying from 4- to 9-celled.
KEY TO THE SPECIES OF BILIMBIA
| On rocks. | |
| Apothecia and spores smaller | 5. B. microcarpa |
| Apothecia and spores larger | 6. B. trachona |
| On other substrata. | |
| On mosses | 2. B. hypnophila |
| On wood or bark. | |
| Spores becoming more than 4-celled | 3. B. naegelii |
| Spores not more than 4-celled. | |
| Apothecia flesh-colored to dark brown | 1. B. sphaeroides |
| Apothecia black | 4. B. melaena |