146 CRYPTOGAMIA. 



20. SQUAMARIA, DC, Nyl. 



1. Squamaria chrtsoleuca var. Daltoni, Tayl. (Tab. 1. fig. 4.) 



Squamaria chrywleuca var. Daltoni, Tayl. in Hook. f. Fl. Antarct. 2, p. 534, tab. 198. 



Hab. Snow line of the Andes of Chili, behind Santiago. — The figure 

 presents the habit of the Lichen, which, since this report was first pre- 

 pared, has been illustrated in the cited Antarctic Flora of Dr. Hooker. 



21. P L A C D I U M, DC, Nyl. 



1. Placodium Paumotense, Sp. Nov. 



P. thallo subcartllagineo adnata e glauco albicante subtiliter pruinoso, 

 laciniis linearibus multifidis irregidariter imbricatis concrescentibusque 

 prtaniusculis nunc sorediatis vel omnino granidatis apiclbus rotimdatis 

 crenatis; hypothallo nigro; apotheciis sessilibus marghie thallode vel 

 tumidido prim inflexo discum vix demtim cequante crenulato, vel ex- 

 cluso discam e piano convexiusculum opacum rufo-nigrum moraine 

 p))'oprio valido nitldulo cinctum ftdclente. 



Hab. Carlshoff Island, Paumotu Group. 



Thallus somewhat cartilagineous, adnate, glaucous-white, very deli- 

 cately pruinose ; lobes irregularly imbricated, here and there growing 

 together, linear, multifid, flattish, more or less besprinkled with soredia, 

 or altogether granulate. Hypothallus black. Apothecia sessile, with 

 a tumid, at length crenulate, thalline margin, which is finally excluded, 

 and the slightly convex, opaque, rufous-blackish disk is bordered only 

 by its strong proper margin. The specimen which afforded this diag- 

 nosis, in 1846, has since been lost from the collections of the govern- 

 ment, and I cannot, therefore, add anything to the above. 



2. Placodium murorum, (Hoffm.) DC. 



Lichen murorum, Hoifin. Enum. p. 63, 9, f. 2. 



Parmdia murorum, Ach. Meth. p. 195; Fr. Lichenogr. p. 115; Lich. Suec. n. 391. 



Placodium murorum, De Cand. Fl. Fr. 2, p. 378 ; Nyl. Prodr. p. 73. 



Lecanora murorum, Ach. Lichenogr. p. 433 ; Syn. p 181. 



Hab. California. 



