THE LICHEN FLORA. OF THE SANTA CRUZ PENINSULA 179 



Apothecia of small to medium size, plane or plano-convex, the disk 

 typically of a beautiful bright clear reddish brown, but varying from 

 light brown to a very dark brown-black; not pruinose; the persistent 

 thalline margin entire to flexuous and slightly crenate; paraphyses 

 slender, distinct, the epithecium brownish or yellowish; thecium 

 bluish, then indigo with I; spores ellipsoid to ovate-ellipsoid, 

 7 ii 



-i /. 



12 17 



Abundant on bark of various trees, especially in the foothills; not 

 rare on old fences. Disk sometimes black from the numerous 

 minute apothecia of a parasitic Thelidium or Conidioclamens. 



Found throughout the world; a variable plant occurring on a 

 great variety of substrata. 



12. Var. CAMPESTRIS Schaerer. 



Lecanora subfusca campestris Schaerer, Spicil. 391. 



Lecanora subfusca campestris Tuck. Syn. N. Am. Lich. 1 : 188. 1882. 



Thallus from contiguous becoming thin and scattered, rougher 

 and granulose warty; gray to grayish white; apothecia very numer- 

 ous, usually small; plano-convex or turgid, often flexuous; the disk 

 bright chestnut to blackish brown; naked; margin entire to minutely 

 crenate. 



A rock-dwelling form of subfusca, occurring on sandstone through- 

 out. 



Of the many varieties of subfusca named by authors, we seem to 

 have, in addition to the above described, only argentata and perhaps 

 allophana, and these I am unable to regard as differing enough from 

 the typical form to merit separate descriptions. In the Tuck. Herb, 

 are specimens labelled Lecanora subfusca v. chlarona collected by 

 Bolander on Quercus or Passania densiflora, and in Marin County 

 on Negundo aceroides and also some collected by Charles Wright, 

 botanist of the U. S. Exploring Expedition. 



In some of my specimens the thallus is very near that of Lecanora 

 chlarona collected by me in the Austrian Alps, but a section of the 

 apothecium shows that they do not have the entirely clear epithe- 

 cium of chlarona but the brownish one of subfusca. It is doubtful if 

 true chlarona has ever been collected in this region. 



