112 



and in Newfoundland, Nylander ; and at Behring's Straits, 



Wright. Eocky Mountains in Colorado, Coulter. Wolf.(*} 



The spores of this species occur in 2 8 -, 3 s -, oftenest 4% and only 

 very rarely 5 8 -. A bisporous condition of /?, from Colorado, alt. 

 13,800 ft. (Coulter), was observed by Mr. Willey to contain spores 

 measuring -|ir mic., and may well be compared with S. bispora, 

 Nyl. Syn.y which has yet no characters to separate it from the 

 present species. 



Fam. 5. PANNARIEI. 



Thallus horizontal, various, in the highest forms distinctly 

 foliaceous, either sub-monophyllous or inany-cleft, coriace- 

 ous -membranaceous, only rarely cartilagiueous, passing 

 then into squamulose conditions, which become in the end 

 crustaceous ; placed upon a conspicuous hypothallus (now 

 obsolete). Gonimous layer variously constituted; very 

 rarely, in whole or in part, of gonidia ; but commonly of go- 

 nimia, which anticipate here, more or less, the typical struc- 

 ture of the next family. 



The structural relations of this group have been considered 

 by Schwendener, I. c., 3, pp. 151, 178, 190, etc.; and reference 

 may be made also to the writer's Genera Lichenum, p. 41. With 

 the appearance of gonimia in the last family (Peltigerei) an im- 

 portant change begins in the Lichen-organism. This change 

 finds further expression and much fuller development in the 

 family now before us, which will be seen to pass, at more than 

 one point, into the next-succeeding Colle-mei, wherein the go- 

 nimia complete their history. 



The spore-history of this far humbler family is embarrassed 



(*) This variety has been well said by Fries (L. E.) to look like young 

 plants of S. saccata, growing on a foreign crust ; the minute fronds, dif- 

 fering only in size from those of a, being connected together and over- 

 run by another semi-crustaceous, paunariifonn, tabulate-granulate thai- 

 las, the darker colour of which is due to gonimia, supplanting here the 

 more common green gonidia of the species ; but this second thallus is 

 taken by recent authors to belong to our lichen equally with the first, 

 or to be (as compare Nylander I. c. under S. bispora) an anamorphosis 

 of that. 



