232 HERRE 



and scurfy, or occasionally obsolete; whitish, ashen, to dusky gray; 

 hypothallus not different in color; KOH faint reddish. 



Apothecia small, sessile, plane or convex; thalline margin soon 

 disappearing; the thin entire, proper margin prominent, paler than 

 the orange-yellow disk; KOH crimson; spores ellipsoid, 



4.9 - 8 



fi. 



9-75 ~ iS-75 



Abundant on trees, especially on jEsculus calif ornicus. 

 A common lichen in Europe and North America, on bark, dead 

 wood, and stones. 



6. CALOPLACA GILVA (Hoffm.) A. Zahlbr. 



Verrucaria gilva Hoffmann, Deutsch. Flor. 2. 1795. 

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

 Placodium cerinum Tuck. Syn. N. Am. Lich. I: 175. 1882. 



Thallus thin, usually definite, soon chinky, granular or warted, 

 areolate or scattered; often disappearing; hypothallus evident, blu- 

 ish black; color gray, ashy, or dusky; KOH crimson. 



Apothecia small to medium, sessile; disk pale yellow to reddish or 

 brownish; plane; thalline margin thin, entire, paler or concolorous; 

 thecium rose-red with KOH; spores ellipsoid to broadly ellipsoid, 

 4.9-9.75 

 10 - 15.75 



A common and variable lichen, occurring everywhere in the foot- 

 hills on trees and old boards, and also on rocks. Found generally 

 over Europe and North America. 



7. CALOPLACA CITRINUM (Hoffm.) Th. Fr. 



Verrucaria citrina Hoffmann, Deutsch. Fl. 2: 198. 1795. 

 Caloplaca citrinum Th. Fries, Lich. Scand. 1 : 176. 1871. 

 Placodium citrinum Leighton, Lich. Flor. Grt. Brit. ed. 3, 163. 



1879. 

 Placodium citrinum Tuck. Syn. N. Am. Lich. I: 174. 1882. 



Thallus effuse, granulose, sub-areolate, lemon-yellow, varying 

 from grayish to greenish. 



Apothecia small, numerous, appressed, the disk yellow or pale 



orange, plane, the pale margin entire; spores ellipsoid, ' {*' 

 KOH purple. 



