360 HERRE 



a. Apothecia without leafy or lobed margin. 

 j. Thallus green, becoming brown or dingy. 



3. fiulverulenta^ 361. 

 jj. Thallus not green or brown. 



k. Thallus silver}' white ; apothecial margin more or 

 less sorediate ...4. pidverulenta argyphcea^ 361. 

 kk. Color bluish slate to dingy black. 



5. ptilverulenta isidiigera^ 3^2. 



I. PHYSCIA ERINACEA (Ach.) Tuck. 



Thallus small, matted or loosely tufted ; naked, white or 

 greenish white ; beneath very white and often covered with a 

 greenish powder; the ascendant lobes more or less flat, sinu- 

 ous, and irregularly notched ; contracting and dilating so as to 

 be knobbed ; marginally ciliate with very many long fibrils, so 

 that the whole plant has a fuzzy appearance ; cilia white, brown, 

 or blackening; apothecia usually abundant, small, scattered ; 

 pedicellate ; the disk convex, black or brownish-black ; more 

 or less bluish-white pruinose, becoming later naked ; margin 

 entire or minutely crenulate. 



Confined to shrubs near the sea shore, occurring in both 

 Lower and Upper California. Southward it is both abundant 

 and luxuriant, but in our territory I have found only scanty 

 specimens on dead or dying shrubs of Arteuiisia californica^ 

 growing on cliffs above the sea near Point San Pedro. 



In the Stanford University herbarium are specimens from 

 Santa Cruz Island, near Santa Barbara, and from Guadalupe 

 Island, Lower California, collected by Mr. R. E. Snodgrass, of 

 Stanford University. The best specimens seen were collected 

 by Mr. LeRoy Abrams at Tia Juana, near San Diego. 

 Borrera erinacca Ach. Lich. Univ. 499. 1810. 

 Physcia erinacea Tuck. Proc. Am. Acad. 4 : 388. i860. 



2. PHYSCIA LEUCOMELA (L.) Michaux. 

 Thallus fruticose, ascendant, elongated, forming diffuse 

 clumps or mats ; the lobes but little divided, narrow to linear, 

 very much intertwined ; margins with numerous stout, branched, 

 black or dark fibrils ; color above varying from greenish or 

 pearly gray to pale dingy brown ; under surface channelled, 

 verj' white ; white powder}' ; sterile. 



