THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 231 



It occurs very finely developed on dry perpendicular rock walls 

 and also on boulders in dry places. 



5. CALOPLACA MURORUM DECIPIENS (Nyl.) 



Lecanora murorum decipiens Nyl. Flora, 8 (note) 1869; p. 106. 1883. 

 Lecanora murorum decipiens Crombie, Brit. Lich. 1: 359. 1894. 



Distinguished by the reduced, crowded, verrucose thallus, with 

 concolorous soredia; lobules very short; apothecia concolorous, scat- 

 tered. 



Rare; on rocks in the foothills. 



4. CALOPLACA VARIABILIS (Pers.) Th. Fr. 



Lichen variabilis Persoon in Ust. Ann. 26. 1794. 

 Caloplaca variabilis Th. Fr. Lich. Scand. !: 172. 1871. 

 Placodium variabile Nyl. Lich. Scand. 138. 1861. 

 Placodium variabile Tuck. Syn. N. Am. Lich. I: 172. 1882. 



Thallus of minute, rather thin areoles, forming a chinky crust, 

 without emgurate margin in our specimens; ashy gray to grayish 

 brown in color; faint reddish or violet with KOH*, CaCl 2 O2 . 



Apothecia numerous, obscuring the thallus, of moderate size, 

 appressed, flat or plano-convex; the disk very dark brown to black, 

 bordered by an entire, at length flexuous margin, which passes from 

 white powdery or paler conditions into concolorous; thecium deep 

 blue with I; in our specimens the contents of the asci generally 

 degenerate, not often formed into spores, these also generally imper- 

 fect, broadly ellipsoid, -^ j. 

 2 14.5 - 17.1 



On igneous rocks in the foothills near Stanford University; too 

 easily passed by, bearing no resemblance to our other representa- 

 tives of the genus. Found in Europe and western North America. 



5. CALOPLACA CERINA (Ehrh.) A. Zahlbr. 



Lichen cerinus Ehrhart, PI. Crypt. Dec. 22, no. 216. 1785. 



Caloplaca cerina A. Zahlbr. Ascolichenes, 228. 1907. 



Placodium cerinum c. pyracea Tuck. Syn. N. Am. Lich. I: 175. 



1882. 



Thallus thin, effuse, granular and contiguous, or becoming chinky 



