THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 77 



A handsome lichen common on rocks in the foothills. The fruit 

 superficially resembles that of the Verrucariacea. Found in the 

 temperate parts of Europe and North America. 



LECIDEACE^E. 



Thallus crustaceous, horizontally outspread, uniform or margi- 

 nally lobed, fissured, areolate to scale-like or squamulose, without 

 rhizoids; alga Proiococcus; with or without a poorly developed cor- 

 tex. Apothecia circular, sessile upon the thallus or rarely innate or 

 elevated; the proper margin clear or black, the apothecia without 

 thalline margin and without algae; hypothecium colorless to black; 

 paraphyses rarely branched, their tips usually more or less thickened; 

 asci usually with 8 spores, in some genera i 8, rarely 16 32; 

 spores colorless or brown in one genus, simple, to plurilocular or 

 muriform. 



KEY TO GENERA. 



Thallus with a cortex; spores 2-8 locular XXII. Toninia 



Thallus without cortex. 



Spores simple, colorless XIX. Lecidea 



Spores not simple. 



Spores muriform, brown XXIII. Rhizocarpon 



Spores not muriform, colorless. 



Spores bilocular XX. Catillaria 



Spores 4-16 locular XXI. Bacidia 



XIX. Lecidea (Ach.) Th. Fr. 



Lecidea Ach. Meth. Lich. 32. 1803. 



Lecidea Th. Fries, Gen. Heterol. Europ. 88. 1861. 



Lecidea A. Zahlbr. Ascolichenes, 130. 1907. 



Thallus crustaceous, varying from uniform to lobate at the cir- 

 cumference, and from small areoles to warty, scale-like, or more or 

 less leafy squamules, without rhizoids, not corticated or with a thin 

 cortex, naked or sorediose; alga Protococcus. Apothecia circular or 

 angulate or irregular from lateral pressure, innate, sessile, or ele- 

 vated-sessile, the proper margin not enclosing algae and varying from 

 clear to black; hypothecium colorless to black; paraphyses un- 

 branched; spores 8 or rarely 16, small, simple, colorless, usually ellip- 

 soid, ovoid, or narrow-oblong, straight or slightly curved. 



