198 HERRE 



Thallus siib-orbiculate, narrowed, cartilaginous-membranaceous ; 

 lobes short, broad, crenately incised, more or less reticulately rugose, 

 and beset with small or dot-like, irregularly scattered, roughened, 

 white soredia; upper surface glaucous gray; herbarium specimens 

 brownish gray; beneath whitish to pale brownish and dusky, smooth, 

 or with white, brown, or black fibrils; KOH greenish yellow to yel- 

 low; medulla and soredia red with CaCl202. 



Sterile with us. 



I have found this widely distributed lichen near the mouth of Ano 

 Nuevo Creek, at an altitude of 100 feet, growing plentifully on the 

 trunks of oaks, and also sparingly on oaks at Santa Cruz. A single 

 specimen was also collected at Devils Canon, growing on sandstone. 



(Named for WilHam Borrer, an eminent EngUsh lichenologist of 

 the first half of the last century.) 



7. PARHELIA OLIVACEA (L.) Ach. 



Lichen olivaceiis L. Sp. Plant. 2 : 1143. 1753. 

 Parmelia olivacea Ach. Meth. Lich. 213. 1803. 

 Parmelia olivacea Tuck. Syn. N. Am. Lich. I: 62. 1882, (in 



part). 

 Parmelia olivacea Herre, Proc. Wash. Acad. Sci. 7: 356. 1906, (in 



part). 



Thallus membranaceous, expanded, orbicular or becoming irreg- 

 ular, appressed; usually smooth and poHshed, but finally wrinkled 

 and rough; lobes rounded, crenate, flat; color olive-brown to very 

 dark brown, almost black; beneath black, with short black fibrils; 

 KOH-; CaClaOa-. 



Apothecia concolorous or chestnut; margin crenate or dentate, 

 to entire; spores short-ellipsoid to globose, 8 in the asci, and also 

 (variety polyspora Herre, new variety), are 16, 18, and 20 in 



the asci, /<• Apothecia very abundant on tree-growing forms 



but rare or wanting on those growing on rocks. 

 Common on trees and rocks throughout. 

 According to all the accessible literature this species has 8 spores, 



7 — 10 

 averagmg /<, but the spore characters of my specimens are 



exceedingly different. 



