36 HERRE 



QQ. Under surface without cyphels. .f 



R. Thallus pale -villous beneath with large, pale, 



naked spots XXXVIII. Lobaria 



RR. Thallus pale or whitish beneath, with brown 

 veins and fibrils ; apothecia adnate on tips 

 of more or less elongate lobes. 



XLI. Peltigera. 

 PP. Without veins or cyphels on under surface. 



S. Spores bi-locular, brown LXIV. Physcia 



SS. Spores simple, ^colorless. 



T. Thallus flat, Oppressed ; under surface brown or 

 black, more or less black fibrillose; apothecia 



scattered over surface XLIX. Parmelia 



TT. Thallus sub-fruticose, compressed; apothecia 

 marginal or on tips of ascendant lobes. 



L. Cetraria 







Fruticose Lichens. 



Plants more or less erect and shrub-like, or drooping and pendulous. 



A. Thallus of two kinds: (i) a horizontal, more or less leafy or granulose 

 one; (2) a more prominent, erect, and caulescent one, really stalks 

 for the apothecia but apparently the plant; simple, and club, cup, or 

 funnel-shaped, or slender and much branched; apothecia scarlet or 



brown XXIV. Cladonia 



A A. Thallus uniform, not two-fold. 

 B. Apothecia globose, terminal; plant tufted, shrub-like, gray. 



XI. Sph&rophorus 

 BB. Apothecia dish or shield-like; terminal, marginal, or more rarely 



scattered. 

 C.. Thallus hair-like. 



D. Black or brown, like tangled mats of fine hair. 



LIV. Alectoria 

 DD. Color not black or brown. 



E. Xhallus erect or decumbent, densely tufted, intricately 

 branched, terete, gray, sterile; on maritime rocks. 



XVI. Dendrographa 



EE. Thallus coarser, gray or pale straw-color, rarely red; tufted 

 i or pendulous, becoming enormously elongated; apothe- 



cia concolorous or pale tan, with fibrillose margin. 



LVI. Usnea 



CC. Thallus not hair-like. 

 F. Plants not gray or green. 

 G. Thallus brown or black. 

 H. Sooty black, very small, compact, sterile: on vertical 



sandstone walls XXIX. Ephebe 



EH. Greenish black or brown, spreading, compressed ; apothe- 

 cia abundant, terminal % L. Cetraria 



