102 GUIDE TO THE STUDY OP LICUeNS. 



5. Thamnolia. 



This genus is represented by one species only. It 

 is quite probable that it belongs to Oladonia ; in fact, 

 that is the position given it by many lichenologists. 



The primary thallus is wanting. The podetia are 

 quite free from warts or excrescences, hollow, simple 

 or sparingly branched. They are widest at the bot- 

 tom, gradually tapering upward, a character not oc- 

 curring in the simpler podetia of Cladonia. Color 

 varies from greenish-gray to pale straw-color. 



No apothecia have been found ; it is propagated by 

 means of soredia, and also vegetatively. 



It occurs upon rock and soil in the higher altitudes 

 and latitudes. 



1. Thamnolia vermicularis. Primary thallus want- 

 ing. Podetia rather long, usually simple, sometimes 

 one or more short branches toward the apex, thin, 

 tapering, sometimes wrinkled longitudinally, color as 

 above. No apothecia, and hence no spores. 



III. LECIDEACE^. 



Stipes and podetia are wholly wanting in this 

 family, which distinguishes it from the preceding 

 families. The apothecia are sessile upon the thallus, 

 discoid, and belong to the fungal type. The disk is 

 generally convex or flattened. The thallus varies 

 from crustose to distinctly foliose, never fruticose. 

 The foliose thalli are entire, not distinctly lobed or 

 branched. 



It must be stated that considerable doubt exists as 

 to the exact limitations of this family. Some of the 



