216 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
hypothecium pale; hymenium pale below and yellowish above: paraphyses simple 
or branched, frequently enlarged and slightly colored toward the apex; asci clavate; 
spores polar 2-celled, ellipsoid or ovoid-ellipsoid, 10 to 16 » long and 5 to 9 ye wide, the 
number of nonpolar spores larger than in most of the species. 
The species seems clear enough as it occurs on old wood, but transitional forms 
of the last certainly occur on trees. 
Generally distributed over the State. On old wood. 
Found throughout the northern United States and northward. Also in southern 
California. Known in all of the grand divisions except Africa. 
Placodium cerinum pyracea of the preliminary reports. 
9. Placodium ferrugineum (Huds.) Hepp, Spor. Flecht. Eur. pl. 45. f, 400. 1857. 
Lichen ferrugineus Huds. Fl. Angl. ed. 2. 526. 1778. 
Thallus crustose and commonly thin, rather smooth and chinky or becoming rugose 
and verrucose, ashy or whitish, usually more or less irregular and variously disposed 
upon the substratum, with a thin layer above the algal cells, but scarcely to be regarded 
as corticate, the whole thallus sometimes becoming scattered and tending to disappear; 
apothecia small to almost middle-sized, 0.3 to 1.3 mm. in diameter, the thalloid 
exciple evanescent and the structure early becoming biatoroid, sessile, the disk flat, 
rust-colored or blackening, frequently subpruinose; hypothecium brown or brown- 
ish; hymenium pale below and brownish above; paraphyses simple or branched, 
commonly enlarged and brownish toward the apex; spores ellipsoid, polar 2-celled, 
11 to 20 » long and 6 to 10 » wide. 
Collected at such remotely separate localities as Mankato, Bemidji, Red Lake, 
and Rainy Lake City. On dead coniferous wood. Easily passed over for a Biatora 
and no doubt generally diffused throughout the State. 
Generally distributed over North America. Found also in Europe and Africa. 
9a. Placodium ferrugineum pollinii (Mass.) Tuck. Syn. N. A. Lich. 1: 177. 1882. 
Blastenia pollinit Mass. Flora 85: 575, 1852. 
Thallus thinner, whitish, and tending to disappear; apothecia biatoroid, becoming 
more or less convex, the proper exciple tending to disappear, the disk olivaceous and 
blackening. 
Distribution in the State quite as that of the species as is also the habitat. 
Elsewhere in North America in New England, Maryland, Illinois, Iowa, and 
Nebraska. Known also in Europe. 
10. Placodium vitellinum (Hoffm.) Hepp, Spor. Flecht. Eur. pl. 44. f. 891. 1857. 
Patellaria vitellina Hofim. Descr. Pl. Crypt. 2:5. pl. 26. f. 2. 1794. 
Thallus crustose-granulate, composed of small rounded or finally squamulose and 
crenate-lobed granules, which may be scattered or grouped into areole-like clusters, 
bright greenish-yellow, forming a more or less broken or rarely continuous layer, 
usually irregular and more or less spread over the substratum, with some suggestion 
of an upper cellular cortex at least over portions of some thalli; apothecia rather 
small, 0.3 to 1.8 mm. in diameter, sessile, the disk commonly flat, tawny-yellow, 
becoming olivaceous, the exciple thalloid and granulate-crenate; hypothecium pale; 
hymenium pale below and yellowish above; paraphyses simple or branched, com- 
monly enlarged and yellowish toward the apex; spores commonly 12 to 32 in each 
ascus (rarely only 8), ellipsoid, 2-celled and simple, 8 to 16 long and 4 to 7 » wide. 
Generally distributed over the State. On rocks and old wood, 
Found throughout North America. Known in all of the grand divisions. 
10a. Placodium vitellinum aurellum (Hofim.) Tuck. Syn. N. A. Lich, 1: 180. 1882. 
Patellaria vitellina aurella Hottm. Deutsch, Fl. 2: 197. 1795. 
Thallus scattered and disappearing; apothecia smaller with entire exciple; spores 
rather more commonly simple. 
