HEREE THE GYROPHORACEAE OF CALIFORNIA. 



315 



KEY TO THE SPECIES. 



Polyphyllous (as to American Bpecies) and always sterile (within 

 our territory so far as known). 

 Thallus smooth, black, often polished; lobes often narrowed, 



with spatulate tips 1 . 



Upper surface more or less covered by a sooty or chaffy scurf. 2. 

 Plants usually one-leaved (seldom many-leaved) and more or less 

 freely fruiting. 

 Apothecia simple, often elevated, not gyrose-plicate; upper 

 surface more or less ridged and reticulate, 

 ltidges hoary with hard, white granules; under side of 



plant smooth, more or less pruinose 3. 



Kidges coarse, without white granules; plant thickly clad 

 with long hairs beneath, or rarely these few or 



reduced to mere papillae 4. 



Apothecia more or less gyrose-plicate. 



Thallus pale, from whitish to mouse color. 



Under surface densely black-hirsute; thallus large to 



very large, ashy white, gray, or mouse color. 

 Under surface not black-hirsute. 



Thallus small, ashy gray or mouse color; beneath 

 grayish or blackish, naked or very rarely 



with fibrils 6. 



Thallus dirty gray or blackish gray; beneath 



smooth, naked, buff to dusky brown 



Thallus light brown to chocolate and blackish. 

 Under surface more or less densely fibrillose. 



Fibrils mostly paler than the lacerate under sur- 

 face; apothecia angulate and stellate, but 



little convex 



Fibrils black; under surface not lacerate; apothe- 

 cia becoming very large, prominent, dome- 

 like 



Under surface not fibrillose. 



Upper surface irregularly papulose-wrinkled; 

 under side smooth, often slightly pitted . . 

 Upper surface not papulose. 



Upper surface covered by intricate, black, 

 indented lines resembling sutures; 



under surface radiately ridged 11. 



Upper surface without special characters; 



under surface smooth, granulose 12. 



G. polyphylla, 

 G, fiocculosa. 



G. reticulata. 



G. rugifera. 



5. G. vellea. 



G. grisea. 

 7. G. arctica. 



8, G. arigulata. 



9. G. pohjrrhiza. 

 G. hyperborea. 



10. 



G. erosa. 

 G. phaea. 



1. Gyrophora polyphylla (L.) Borr. & Turn. Lich. Brit. 214. 1839. Plate 68, a. 



Lichen polyphyllus L. Sp. PI. 1150. 1753. 



Umbilicaria polyphylla Tuck. Syn. N. Amer. Lich. 1: 85. 1882. 



Thallus small to medium size, many-leaved, crinkled, cespitose, the surface smooth, 

 often polished, irregularly much lobed and dissected, the erectish lobules often slender 

 with dilated and rounded tips; margin crenate, dentate, unevenly cut, or erose, 

 sometimes minutely and excessively dissected and crisped ; color black or very dark 

 brown; under surface naked, finely granulate, dull black. 



Sterile with us and very rare in fruit anywhere; I have never seen specimens with 

 apothecia. 



