THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 169 



Porina leioplaca Ach. Lich. Univ. 309, pi. 7. f. 2. 1810. 

 Pertusaria leioplaca Schaerer, Spicilegia, 66. 1823. 

 Pertusaria leioplaca Tuck. Syn. N. Am. Lich. I: 214. 1882. 



Thallus determinate, cartilaginous, thin to very thin, smooth, 

 becoming folded or undulate, and fissured; color whitish or creamy; 

 KOH yellow. 



Apothecial warts scattered, adnate, hemispherical to irregular, 

 smooth, somewhat flattened; ostioles solitary or few, minute, punc- 

 tiform, indistinct or blackening; spores varying, 3-4-5- and 6 in the 



27 3 ^ 

 asci; rarely only two; oblong ellipsoid; - - /*. 



. 47 " 75 



On trunks and limbs of trees in the foothills. A cosmopolitan 

 lichen. 



LECANORACE^). 



Thallus crustaceous, uniform or marginally lobed, or exceptionally 

 fruticose, branched and decumbent; without rhizoids, and with or 

 without cortex; alga Protococcus or Pleurococcus. 



Apothecia permanently innate in the thallus or sessile, circular, 

 with a thalline margin enclosing algae; proper margin lacking or 

 imperfectly developed; hypothecium clear, usually upon a layer of 

 algae; paraphyses unbranched and free, or branched and agglutinate; 

 asci usually 8-spored, sometimes 2-8, or 8-32 sporous; spores color- 

 less, rarely brownish, simple, bilocular to multilocular and muri- 

 form; thin walled. 



KEY TO GENERA. 



A. Spores simple. 

 B. Paraphyses unbranched, free. 



C. Spermatia thread-like, straight or curved . . .XLIII. Lecanora 

 CC. Spermatia ellipsoid, straight; thallus egg-yellow. 



XL VII. Candelariella 



BB. Paraphyses branched and net-like XLIV. Ochrolechia 



A A. Spores not simple. 



D. Sterigmata exobasidial; spores bilocular. 

 E. Thallus gray or brown; spermatia thread-like, straight 



or curved XLV. Lecania 



EE. Thallus egg-yellow; spermatia ellipsoid, straight. 



XL VII. Candelariella 

 DD. Sterigmata endobasidial ; spores 2-4 locular. 



XL VI. Placolecania 



