THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 35 



Foliaceoiis Lichens. 



A. Thallus gelatinous when wet; color always dark; algae blue-green 

 iCyanophyce^.) 



B. Algae Scytonema XXX. Polychidium 



BB. Algae Nostoc. 



C. Thallus dark green without cortical layer XXXII. CoUema 



CC. Thallus usually lead-colored, with distinct cortical layer. 



XXXIII. Lcptogmm 

 A A. Thallus not gelatinous when wet. 



D. Apothecia never present. 

 E. Thallus dark. 



F. Plant apparently black, the surface coveied with black isidia. 



XXXIX. Sticta 

 FF. Plant dark brown, sub-f ruticose ; the ascendant, irregularly 



cut lobes with narrow white edge L. Cetraria 



EE. Thallus green or pale. 



G. Yellowish green with gray soredia; beneath villous or with 



naked pale spots XXXVIII. Lobaria 



GG. Plant more or less orbicular, often very large, grey, yellowish 

 or bright green; beneath black, usually brown-maigined, 



more or less black-fibrillose XLIX. Parmclia 



DD. Apothecia usually present and abundant. 



//. Thallus attached at a single point near the center by an umbili- 

 cus. 

 /. Apothecia visible to naked eye; thallus large or of medium size. 

 /. Apothecia adnate, gyrose; thallus brown. . .XXV. Gyrophora 

 JJ. Apothecia immersed, appearing as minute dark specks on the 



ashy gray thallus II. Dermatocarpon 



II. Apothecia not visible to naked eye; thallus very small, dark 

 olive or blackish brown, expanded or ascendant. 



XXXIV. Ileppia 

 HH. Thallus attached by numerous rhizoids, not umbilicate. 

 K. Apothecia adnate on undei side ot marginal lobes. 



L. Algaae Nostoc; spores 2-4 locular XL. Nephroma 



LL. Algae Protococcus; spores simple LI. Nephromopsis 



KK. Apothecia always on upper surface of thallus. 

 M. Thallus bright yellow or oiange. 



N. Apothecia chestnut; spores simple, colorless. 



L. Cetraria 

 NN. Apothecia yellow or orange. 

 0. Spores polai-bilocular, colorless, 8. 



LIX. X author ia 



00. Spores simple, 16 to 60 XLVIII. Candelaria 



MM. Thallus not bright yellow 01 orange. 



P. Thallus horizontal, orbicular or variously lobed; undei 

 surface with veins or cyphels. 

 Q. Under surface with small white cyphels, villous or 

 fleecy XXXIX. Sticta 



