Lichens of Santa Cruz Peninsula 339 



Common on fences throughout the foothills and to the summit 

 of the range. 



This species may be recognized at once by the narrow but 

 conspicuous white edge of the thallus. 



Lichen chlorophyllus Humboldt, Fl. Fri. Spicil. 20. 1793. 

 Cetraria chlorophylla Wahl. 



5. CETRARIA LACUNOSA STENOPHYLLA Tuck. 



Thallus becoming fruticose, deeply and irregularly lobed ; 

 lobes long, lax or sub-pendulous, narrow to linear, deeply chan- 

 nelled ; margins laciniate, erose, and minutely tuberculate ; 

 color pale sage-green or gray-green ; some specimens with a 

 brownish cast; beneath white, or very pale. Apothecia ter- 

 minal ; disk chestnut ; margin crenate or more rarely entire. 



Habitat, trees. 



Very common in the mountains above 1500 feet. Especially 

 abundant on the limbs of Pseiidotsuga taxifolia^ which it some- 

 times clothes to the exclusion of all other lichens. 

 Cetraria lacunosa stenophylla Tuck. Syn. N. Am. Lich. i : 



35. 1882. 



6. CETRARIA GLAUCA (L.) Acharius. 



Thallus membranaceous, foliaceous, sinuately or irregularly 

 broad-lobed ; the crenate or dissected edges of the lobes fre- 

 quently sorediate, thickened, and prolonged into more or less 

 conspicuous coralloid branchlets ; color of plants growing on 

 earth : greenish gray marginally, varying to olive- or brown- 

 gray centrally, or sometimes the whole plant a glaucous gray- 

 green ; beneath wrinkled or reticulate and black, with now and 

 then a chestnut margin ; fibrils wanting, or occasionally scat- 

 tered and very minute. 



Color of plants on trees : pale sage-green, varying to colors 

 as dark as those of earth-growing forms. Beneath black, fad- 

 ing into pale brown, with broad white margins. 



Always sterile with us. 



Everywhere on trees in the mountains above 1,500 feet, but 

 at no place very abundant. Usually on the limbs of Psetido- 

 tsiiga taxijolia^ mixed with Usneas^ Sphcerophortcs globosuSy 

 and Cetraria lacunosa stenophylla. 



