208 KItfODINA. 



entire thalline margin often excluded, and the black apothecia 



lecideoid. Spores as in a. Exs. Anzi Lich. Langob. n. 321. 



Zw. exs. n. 61. Ejusd. exs. n. 68, /?. Nyl. Lich. Par. n. 43. 



c. . tephraspiSj Tuck. herb. ; thallus thickened ; of crenulate 

 but soon turgid, verrucose - irregular and crowded areoles; 

 brownish-ash-coloured ; apothecia at length middling-sized, be- 

 coming turgid ; but the thalline margin persistent. Spores as 

 in a. Lecanora, Tuckerm. Suppl. 1, 1. c. p. 425. 



d. confragosa, Nyl.; thallus coarser; verrucose, often con- 

 glomerate, and now sub-lobulate ; white ; apothecia at length 

 middling-sized. Spores a little larger than in the preceding 

 forms. Nyl. I. c. max. p. Exs. Fr. Lich. Suec. 283. 



e. exigua, Fr. ; thallus reduced ; now scurfy, or disappearing ; 

 whitish ; hypothallus obsolete ; apothecia small to very small, 

 finally convex; the entire margin at length crenulate, or ex- 

 cluded. Spores as in a, or a little smaller. Nyl. I. c. 



Spores now occurring from 8 to 12-16-20-30 in the thekes. R. 



polyspora, Th. Fr. Scand. p. 206. Lecanora, Nyl. 



Trees, stones, and dead wood, throughout North America, 

 Muhlenberg Catal. 1818. a, common on bark, and noticeable 



by its dark thallus. &, only on rocks, where its colour, flattish 



areoles, and lecideoid fruit, sufficiently indicate it. c, also a 



rock-lichen, I have tried to bring under b, taking our plant for 

 a better developed condition (with fruit now 2 mm - in width) of 

 such European lichens as Zw. exs. n. 68, J, andHepp. Lich. Eur. 

 n. 646 ; both which are referred by their authors to E. atrocin- 

 erea ; as the first-named is also by Koerber : but cannot, for the 



present, but keep it separate. d offers apothecia larger than 



in any other form of the species except the last-named ; and 

 its coarse, white thallus aids also in making E. sophodes, in this 

 condition, conspicuous on the rocks and the earth of our Pacific 

 Coast; where a bark-form (Lecanora Roboris, Duf., e Nyl. in 

 Mandon Lich. Mader. n. 38) is also found, inhabiting the Oaks of 

 California. The last appears as yet to be rare with us else- 

 where. e, on bushes, trees, and dead wood, everywhere : the 



smallest form ; though passing into the tree-form of d. 



9. R. Hallii, Tuckerm. ; thallus cartilagineous, contiguous, 

 chinky; from pale-brownish becoming light-umber-coloured; 

 on a black hypothallus ; apothecia smallish, biatorine, adnate, 

 plano-convex ; disk passing from reddish- into blackish-brown, 



