62 



Podetia sometimes whorled throughout along the main axes, or with oc- 

 casional single branches between whorls; peripheral branches upright, or 

 in older plants curving or nodding, with ultimate branches in clusters of 

 three or more, sometimes distinctly parallel, podetial surface smooth, or in 

 older plants verruculose (with minute warts). 



3. C. mitis 



Podetia rarely polytomous, and usually dichotomous, (two-forked), straw 

 colored, greenish or brownish. 



KOH+ pale yellow; outer podetial layers persistent, monopodial (single- 

 stemmed) appearance clear in large axes; podetial surface smooth, or 

 rough in older plants. 



4. C. tenuis 



KOH — monopodial appearance not so definite, podetia irregularly 

 branched or subdichotomously divided, podetial surface rough with dis- 

 integrating gonidia as plant matures, gonidia greenish, yellowish or 

 whitish, darkening. 



5. C. impexa 



Podetia in regular, smooth, compact colonies, plant masses often with 

 an even, curving top, the podetia being all of nearly equal length; poly- 

 tomous (many-branched), with whorls of branches around gaping axils, 

 whitish or pale gray; KOH—, outer podetial layers often disintegrating, 

 surfaces arachnoid. Distinctive because of the smoothly rounded masses. 

 (PI. l,f. 1.) 



6. C. alpestris 



Subgenus 2. Pycnothelia. Ach. Primary thallus granular-crustaceous, per- 

 sistent. Podetia short, H inch to one inch tall, stout, simple or short- 

 branched, terminating in blunt tips. Apothecia small, brownish-red. 

 "Resembling minute cacti." 



7. C. papillaria 



Subgenus 3. Cenomyce (Ach.) Th. Fr. Primary thallus foliaceous (with 

 leaf-like squamules), persistent, or sometimes disappearing. 



Series A. Cocciferae Del. Apothecia scarlet or rarely flesh-colored or whit- 

 ish in some color forms. 



Subglaucescentes Vainio. Primary squamules grayish green above, white 

 beneath, podetia whitish to grayish-green, sometimes fertile with rather 

 small scarlet apothecia, or sterile with blunt or pointed apices, mostly 

 decorticate (without a definite outer cortex), decorticate areas farinose- 

 sorediate or granulose. 



Podetia usually basally corticate, but with the cortex usually discontinu- 

 ous above, below apices, KOH — . 



8. C. Floerkeana 



Podetia sometimes basally corticate, but above wholly decorticate, and 

 farinose-sorediate, KOH — . 



9. C. bacillaris 



