184 HERRE 



cium blue with I, the asci yellowish or reddish-yellowish; epithe- 



3.6 7 



cium brownish; spores 8, ovoid, - - , 



' 7.5 12.25 



Described from a small specimen collected on the summit of Loma 

 Prieta, altitude 3793 feet. Near Lecanora cinerea, from which it is 

 markedly separated by the small spores and the rough surface of the 

 areoles, as well as the medullary reaction with I. 



A lichen of northern Europe. 



20. LECANORA CINEREA (Ach.) Somm. 



Lichen cinereus (?) Linne, Mantissa, I, 132. 1767. 

 Lichen cinereus Ach. Lich. Suec. Prodr. 32. 1798. 

 Lecanora cinerea Sommerfeldt, Suppl. Fl. Lapp. 99. 1826. 

 Lecanora cinerea Tuck. Syn. N. Am. Lich. I. 198. 1882 (in part). 



Thallus effuse, or more or less determinate, of uniform smooth 

 areoles separated by a net-work of irregular chinks or fissures, or 

 else of separate distinct areoles; the black hypothallus not very evi- 

 dent; color varying from whitish to ashy or brownish gray, or in 

 shaded situations quite dusky; KOH yellow, then blood-red or brick- 

 red; CaCl 2 O 2 - ;!-. 



Apothecia one to several in an areole, small to medium, at first 

 immersed with concave disk; eventually emerging, then sessile, the 

 disk plane, black, not pruinose; margin entire, persistent; paraphy- 

 ses somewhat agglutinate, their tips brownish; hymenium bluish, 

 then tawny with I; spores 8 or sometimes but 6 in the asci, round- 



ellipsoid, ~^ 2 I*. 



On rocks throughout; generally distributed over the North Tem- 

 perate Zone. 



With us the apothecia are not very well developed, the spermo- 

 gonia however being very numerous. 



21. LECANORA GIBBOSA (Ach.) Nyl. 



Lichen gibbosus Ach. Lich. Suec. Prodr. 30. 1798. 



Lecanora gibbosa Nyl. Lich. Scand. 154. 1861. 



Lecanora cinerea c. gibbosa Tuck. Syn. N. Am. Lich. I: 198. 1882. 



Thallus determinate, thickish, of rounded areolae or warts, their 



