PHYSCIA. 69 



In size and general character comparable rather with P. 



speciosa, but a quite distinct member of the present group. 



2(e). P. granulifera (Ach.) Tuckerm. herb. ; thallus cartila- 

 gineous, appressed, glaucescent, and white, pruinose at least at 

 the tips, and besprinkled with white, soon powdery granules ; be- 

 neath corticate, pale, with black fibrils ; lobes multifid, dentate- 

 crenate, the margins neither elevated nor powdery ; apothecia 

 smallish to middling-sized, the inflexed margin crenate. Spores 

 ^^ mic. Parmelia, Ach. Syn. p. 212, P. speciosa, v. granu- 

 lifera, Tuckerm. Obs. Lich. 1, 1. c. p. 390, in part. 



Trunks ; Pennsylvania (Muhlenberg], Ach. Syn. 1814. Mary- 

 land, Tuckerman. Illinois, Hall. 



2(/). P. comosa (Eschw.) Nyl.; thallus sub-stellate, becom- 

 ing erectish and diffusely casspitose, smooth ; beneath ecorticate 

 and very white ; lobes abbreviated, dilated upward ; the margins 

 (and at length the whole upper surface) beset with long, branched 

 fibrils of the same colour ; apothecia middling-sized to largish, 

 obliquely pedicellate ; the pruinose disk enclosed by a thin, cre- 

 nate, at length radiately lobate, ciliate border. Spores bilocu- 



lar, J^ mic. Parmelia comosa, Eschw. Bras. p. 199. Physcia, 



Nyl. Syn. 1, p. 416. P. speciosa, v. galactophylla, Tuckerm. I. c. 

 p. 392, & Lich. exs. n. 82. P. leucomela, v. galactophylla, Nyl. 

 Syn. 1, p. 415. Parmelia galactophylla, Willd. Jierb. 



On trees; Pennsylvania (Muhlenberg), Hoffman D. Fl. 1796 ; 

 and occurring also rarely, and. only infertile, northward to Maine, 

 Oakes; but throughout the Atlantic and Gulf States southward; 

 as also in Ohio, Lea ; Illinois, V. d. Bosch j and Mexico, Nylan- 



der. The lichen of Eschweiler cannot be distinguished from 



P. speciosa, v. galactophylla by merely the numerousness of the 

 fibrils ; and it is observable that the Parmelia echinata, Tayl., 

 which is reduced by Nylander (Syn. I. c.) to Physcia comosa, is 

 exactly (Tayl. herb. !) what the present writer published as 

 galactophylla. 



2(g). P. leucomela (L.) Michx. j thallus ascendant and elon- 

 gated, mostly smooth, either sub-stellate, with the lobation of P. 

 speciosa, when the tips are now similarly revolute and white- 

 sorediate, or at length diffuse, and the linear, attenuated, 

 densely intertangled lobes more remotely and irregularly divided; 

 beneath ecorticate and very white, the margins beset with strong, 



