p 64 PARHELIA. 



but the same reaction is afforded by a similarly white-edged 

 Californian lichen with spores of ~ mic. ; and as well by a 

 specimen from Arctic America (Herb. Hook.) scarcely otherwise 

 differing from the common northern P. caperata. 



16. P. conspersa (Ehvh.) Ach.; thallus dilated, cartilagineous- 

 membranaceous, laciniately much-divided, smooth and more or 

 less polished, but the centre often isidiophorous, greenish-straw- 

 coloured; beneath brown, or blackening, or at length black, 

 with similarly varying fibrils, which are now mostly obsolete ; 

 lobes sinuately cut, passing often into narrowed, pinnatifid, at 

 length densely complicate conditions; apothecia middling to 

 large; disk chestnut; margin sub-crenulate. Spores ellipsoid, 



1^. mic. Ach. L. U. p. 486. Fr. L. E. p. 69. Nyl. Syn. 1, 



p. 391. 



Rocks and stones (and, degenerate, on dead wood) very com- 

 mon at the north ; and, in the mountains, southward. Northern 

 and middle States, Muhlenberg Catal. 1818, and throughout the 

 upper districts of the southern, Ravenel, etc.; as also in the 

 mountains of Texas, Wright ; New Mexico, Fendler; and Mex- 

 ico, Nylander. Rocky Mountains, Hall. On the western Coast, 

 Douglas; Bolander. Arctic America, Richardson. 



16(&). P. leucochlora, Tuckerm.; lobes closely appressed and 

 compaginate, sinuately more or less piunatifid, rugulose, from 

 glaucescent becoming pale-straw-coloured j apothecia smallish ; 



disk chestnut. Spores roundish-ellipsoid, -yy- mic. Tuckerm. 



in Nyl. Syn. I, p. 392. 



On Bald Cypress, Mississippi (Dr. Veitcli], Tuckerman I. c. 

 1860. South Carolina, Dr. J. H. Mellichamp. Florida, Ravenel. 



Louisiana, Hale. The apothecia of P. conspersa exceed at 



length 15 mm - in width, and the spores I3 mmm - in length; but the 

 apothecia of the present average 2-3 mm - and only rarely reach 

 4mm. j n width, and the rounded spores appear to be also smaller. 

 The chemical differences of P. leucochlora, treated with chloride 

 of lime, and with potash, pointed out by the present writer 

 (Amer. Naturalist, April, 1868) as by Nylander (Flora, 1869, p. 

 293) will not here be dwelt on ; but the plant is otherwise not 

 without interest. 



16(c). P. molliuscula, Ach.; Everniseforin, the narrowed 

 lobes sub-stellate, or loosely intricate, dichotomously more or 



