PLACODITJM. 171 



North America (Lecan. miniata), Muhlenberg Catal. 1818. 

 Arctic America, Richardson. Maritime rocks, Massachusetts, 

 Tuckerman. Coast of California, Bolander (rather resembling 

 Amphiloma Heppianum, Miill. ; Kabenh. n. 671, which it is diffi- 

 cult to separate). Beside this yellow one, there is a Californian 

 form with all the features of the present except that the colour 

 is dark-orange, in which respect it suggests P. elegans ; this may 

 be called v. miniatum. 



4(&). P cirrochroum (Ach.) Hepp. ; thallus of P. murorum 

 but small, and perhaps thinner, and bursting at the centre into 

 lemon-coloured soredia ; the tips of the peripheral lobes more or 

 less white-pruinose ; [apothecia rare and not seen here, minute. 



" Spores oblong, ^ mic."] Ach. Syn.p. 181. Koerb. Parerg. 



p. 49. Parmelia murorum, /., Fr. L. E. Lecanora, Schcer. 

 Enum. p. 64. 



Eocks containing lime, Willoughby Lake, Vermont. Prof. W. 

 G. Farlow. 



5. P. fulgens (Sw.) DC.; thallus foliaceous-crustaceous, or- 

 bicular, soft and friable, closely appressed ; pale-yellow or lemon- 

 coloured ; made up of narrow, laciniate-multifid, and crenate, 

 flexuous, concrete lobes, which become radious-plicate at the 

 circumference ; apothecia of middling size, sessile, zeorine ; 

 tawny-red ; the pale, irregular, thalline margin finally excluded 

 by the swelling disk, which is bordered by a thin, entire, proper 



one. Spores ellipsoid, sub-simple, ^ mic. Parmelia, Fr. 



L. E.p. 119, a. P.friabilis, Schcer. Spicil. p. 426. 



b. bracteatum, Ach. ; thallus passing into a verrucose-lobulate- 



crust; the radious circumference disappearing. Schcer. I. c. 



P. fulgens v. alpinum, Th. Fr. Lich. Arct. p. 81. 



Calcareous soils. Greenland (b), Valil e Th. Fr. I. c. 1861. 

 On the North Platte in Nebraska, and Wyoming (a, 6), Hayden. 



Montana, M. A. Brown. The spores of the variety, though 



often simple, occur also in variously imperfect (or even perfect, 

 according to Koerb. Syst. p. 112) bilocular conditions; and I ob- 

 serve not wholly dissimilar spores in some of my foreign speci- 

 mens of a. Both forms belong naturally together ; and to Pla- 

 codium. 



6. P. eugyrum, Tuckerm. ; thallus crustaceous, orbicular,, 

 adnate, applanate; from dirty-brownish-green becoming dark- 



