258 HERRE 



white or pale, clothed more or less with simple white fibrils. KOH 

 yellow; medulla not colored yellow by KOH. 

 Apothecia black, usually pruinose; margin entire; spores 



5 - 8.5 



-^p. 



14.5 - 19.5 



On stones and twigs; abundant along the highest peaks of the 

 range and one of the commonest and most widespread of lichens. 



7. PHYSCIA AIPOLIA (Ach.) Nyl. 



Lichen aipolius Ach. Lich. Suec. Prodr. 112. 1798. 

 Physcia aipolia Nyl. Flora, 53 : 38. 1870. 

 Physcia aipolia Tuck. Syn. N. Am. Lich. I: 73. 1882. 

 Physcia aipolia Herre, Proc. Wash. Acad. Sci. 7: 363. 1906. 



Thallus orbicular, expanded, appressed; lobes much cleft, sinuous, 

 separate and distinct, or coalescent and imbricate; very thickly 

 sprinkled with small white sub-epidermal spots; surface smooth, 

 without soredia; color white or bluish white; beneath dark or black, 

 usually densely clothed with black hispid fibrils; medulla yellow 

 with KOH. 



Apothecia numerous, usually bluish pruinose; disk brownish 

 black; margin thick, prominent, more or less crenate; spores 



15 ~ 25 



Common on twigs and trunks throughout our range; particularly 

 well developed on JEsculus californicus above 2000 feet. Abundant 

 on rocks along the summit of the range. A very common and wide- 

 spread lichen. 



8. PHYSCIA TRIBACIA (Ach.) Tuck. 



Lecanora tribacia Ach. Lich. Univ. 415. 1810. 

 Physcia tribacia Tuck Lich. Am. Sept. No. 85. 

 Physcia tribacia Tuck. Syn. N. Am. Lich. I: 75. 1882. 

 Physcia tribacia Herre, Proc. Wash. Acad. Sci. 7: 364. 1906. 



Thallus more or less orbicular, usually rather small, much lobed; 

 lobes short, in tricatelylaciniate; their margins upturned, much-dis- 

 sected, granulate, becoming lined with confluent soredia; center of 

 thallus sometimes converted into a granulate or sorediate crust; color 



