2298 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
roughened crust toward the center, sea-green varying toward whitish or brownish, 
beneath whitish with rhizoids of the same color; apothecia small, 1.5 to 3.5 mm. in 
diameter, sessile, the disk flat or slightly concave or convex, dark brown to black or 
whitish-pruinose, the margin entire or crenulate; hypothecium pale or yellowish or 
brownish; hymenium pale or brownish, the latter especially above; paraphyses simple 
or more commonly branched, enlarged and brownish toward the apex; asci clavate or 
long-clavate; spores oblong to ellipsoid, 15 to 24 # long and 8 to 11 » wide. 
Generally distributed over the State. On trees and rocks. 
The plant is distributed throughout North America and is cosmopolitan in its 
foreign distribution. 
EXPLANATION OF PLATE 47.—See page 226, 
6a. Physcia stellaris apiolia (Iloffm.) Nyl. Not. Sillsk. Faun, Flor. Fenn. 5: 111. 
1861. 
Lobaria apiolia Hoffm. Deutsch. Fl. 2: 152. 1795. 
Thallus darker below and becoming black with rhizoids of the same color; apothecia 
seldom pruinose and more commonly showing a crenulate or even crenate margin. 
Distributed throughout the State. On igneous and metamorphic rocks. The 
darkened condition below has been observed in tree forms as well. 
The American distribution seems to be the same as that of the species. Known 
also in Europe. 
7. Physcia tribacia (Ach.) Nyl. Flora 64: 537. 1881. 
Parmelia tribacia Ach. Lich. Univ. 415, 1810. 
Thallus closely adnate, but the margins of the lobes strongly ascendant, orbicular 
or more commonly occurring in large irregular patches, sometimes forming a subeon- 
tinuous granular crust toward the center, when having a definite outline small to 
middle-sized, 20 to 75 mm. in diameter, the lobes short and imbricated with erose- 
granulose, or rarely crenate edges, usually wide in proportion to length, but rarely 
more branched, elongated and narrower; sea-green, below whitish with scattered 
fibrils of the same color; apothecia small, 1.5 to 2.5 mm, in diameter, sessile or sub- 
sessile, the disk flat or slightly concave, black or blackish brown or sometimes whitish- 
pruinose, the margin entire or crenulate; hypothecium yellowish; hymenium pale or 
slightly brownish below and sometimes darker brownish above; paraphyses simple 
or rarely branched toward the commonly enlarged and brownish apex; asci clavate 
or cylindrico-clavate; spores oblong to ellipsoid, 16 to 23 long and 7 to 10 ye wide. 
The plant is generally distributed over the State and is easily known in its peculiar 
forms by the thallus. Such forms, however, as number 580, from Blueberry Island, 
with much elongated and narrowed lobes will probably eventually have to be sepa- 
rated. But the last is connected with the usual form of the species by such interme- 
diate forms as number 571 from the same island. On trees and rocks, and the tree 
forms commonly somewhat more closely adnate and less imbricated. 
Distributed throughout North America and also well known in Europe, 
8. Physcia hispida (Schreb.) Tuck. Syn. N. A. Lich. 1: 75. 1882. 
Lichen hispidus Schreb. Spic. Fl. Lips. 126. 1771. 
Thallus small, 6 to 28 mm. in diameter, but quite inclined to grow in dense clusters 
covering larger areas, sometimes subadnate and stellate but more commonly ascendant 
and diffusely cespitose, the lower cortex scarcely continuously cellular, the lobes 
usually somewhat elongated ,jimbricated, and branched, the apices rounded or crenate, 
swollen toward the ends by a large air space between the medullary tissue and the 
lower cortex, usually open upwardly, making the air space a terminal cavity, clothed 
more or less throughout with long, commonly dark fibrils; sea-green, beneath white 
and clothed more or less with light or darker rhizoids; apothecia small, 1 to 2.5 mm. 
