THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 1 93 



Theloschistes concolor Tuck. Syn. N. Am. Lich. 1: 51. 1882. 

 Theloschistes concolorYierre,Vioc.'^dis\i. Acad. Sci. 7: 349. 1906. 



Thallus foliaceous, appressed, the narrow lobes more or less dis- 

 sected; quite small; color yellow, greenish-yellow, or pale; often an 

 ashy white, pale beneath. 



Apothecia small, yellow to orange; spores numerous, 20 to 60 in 

 the asci, simple, or apparently one-septate. 



On trees; also on leaves of a Yucca, at Stanford University, asso- 

 ciated with Lecanora ha gent and Buellia myriocarpa. 



An inconspicuous lichen of wide distribution in general, but appar- 

 ently rare with us. 



XLIX. PARMELIA (Ach.) DeNotrs. 



Parmelia Ach. Meth. Lich. 153. 1803. 

 Parmelia DeNotaris, Giorn. Bot. It. 189. 1847. 



Thallus foliaceous, appressed, expanded laterally and often very 

 large, variously lobed or lacinate, often imbricate; the lower surface 

 usually black, or dark brown, often brown margined, generally more 

 or less black fibrillose; in a few species not occurring with us fastened 

 by a central umbilicus; upper surface often sorediate or isidiose. 



Apothecia shield-Kke, scattered, sessile or often sub-pedicellate; 

 paraphyses imbedded in a firm jelly, usually branched and septate; 

 spores small, elhpsoid, ovoid, or globose, colorless. 



This enormous genus of 400 species or more contains the largest 

 and most conspicuous foliaceous lichens of our flora and is well 

 represented both in number of species and of individuals. 



KEY TO THE SPECIES. 

 A. Thallus dark. 



B. Bright shining brown to dull brown or nearly black. 

 C. Apothecia present, often abundant. 

 D. Surface smooth, often polished. 



E. Medulla not colored by CaClaOz 7. oUvacea 



EE. Medulla red with CaClOj 8. glabra 



CC. Sterile. 



F. Surface covered with short papillae 9. exasperata 



FF. Surface covered with a concolorous scurfy growth 



or isidia 10. fiiliginosa 



BE. Thallus dusky gray to dark brown ; with conspicuous erumpent 



soredia 11. conspurcata 



A A . Thallus some shade of green. 



