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_

1. Bilimbia sphaeroides (Dicks.) Koerb. Syst. Lich. 213. 1855.

Lichen sphaeroides Dicks. Pl. Crypt. Brit. 1: 9. pl. 2. f. 3. 1785.

Thallus of minute, gray-green, often heaped granules, these forming a
continuous, thin or thicker crust; apothecia minute to small, 0.2 to 0.4
mm. in diameter, adnate, flesh-colored to red-brown, flat to convex and
subglobose, the inconspicuous, concolorous exciple soon covered;
hypothecium and hymenium pale; paraphyses usually coherent-indistinct;
asci clavate; spores fusiform-ellipsoid, 4-celled, 12 to 20 mic. long
and 4 to 6 mic. wide.

Collected on Little Mountain, in Lake County. On a rotten log in a wood.
Rare in Ohio, and its distribution unknown.

The plant is typical internally, but is young with small, flat or
slightly convex, light-colored apothecia.

2. Bilimbia hypnophila (Ach.) Th. Fr. Nov. Act. Reg. Soc. Sci. Ups. III.
3: 283. 1861.

_Lecidea hypnophila_ Ach. Lich. Univ. 199. 1810.

Thallus of minute, usually crowded, sometimes confluent granules, these
forming an ash- or green-gray, thin, leprose or subgranulose, sometimes
scattered and disappearing crust; apothecia minute to middle-sized, 0.2
to 0.75 mm. in diameter, light brown to black, adnate to sessile,
scattered or clustered, becoming strongly convex and the exciple
becoming covered; hypothecium pale or darker brown; hymenium pale, or
tinged brown below and more plainly brown above; paraphyses coherent,
semi-distinct to indistinct; asci