OF ARTS AND SCIENCES. 385 



smaller brandies of trees, Texas, Mr. Wright. Monterey, California, 

 Dr. Gregg. Delicately downy ; the smallest states with the habit of 

 the species, but more slender : the larger ones scarcely distinguishable 

 ■ from the next, which occurs pubescent according to Swartz (Wallr. 1. c.) 

 and Fries (Lichenogr. p. 28). Apothecia sparingly radiate-ciliate, or 

 oftener entire. 



Var. y. FLAViCANS, Wallr. 1. c. ; Eschw. Bras. p. 224. Parmelia 

 dein Borrera, Ach. Physcia, DC. ; Nyl. Enum. Gen. 1. c. On trees. 

 South Carolina, 3fr. Ravenel. Elongated, as the last, but smooth; 

 pale yellow above ; the branches compressed at the axils, and often 

 channelled : apothecia with a thin, not ciliate, but obsoletely crenulate 

 thalhne margin, which at length disappeai-s, when the disk (as in other 

 species) appears to possess a thin, more or less evident proper margin. 

 iJouisiana, on trees, fertile, Dr. Hale. Wallroth (Naturgesch. der 

 Flecht. 2, pp. 333-340) was perhaps the first to connect the above 

 Lichens as forms of one species ; but his view embraces plants removed 

 even generically from the present type, and others of doubtful relation 

 to it. Eschweiler follows Wallroth as respects his own Brazilian spe- 

 cimens, and also adopts the general view of the former. The rich col- 

 lections of Mr. Wright, in Texas, where at least two of the forms occur, 

 sufficiently show that the elongated Southern Lichens are inseparable 

 from P. chrysophtliahna, except as varieties. Physcia exilis, Michx. 

 Fl. Bor. Amer. 2, p. 327 {Borrera, Ach. ; Parm. chrysoplithalma, c, 

 Fr. Lichenogr. p. 75 ; Physcia Jlavicans, var. exilis, Nyl. 1. c.) from 

 trees in Carolina, (Bosc, Ilichaux,) appears to be a smallish, slender, 

 pallescent condition of the present variety. I have Louisiana specimens 

 (Dr. Hale) which entirely resemble a South American Lichen referred 

 to P. exilis in Herb. Berol. — P. chrysophthalma is perhaps (as sug- 

 gested by Schi\3rer, Spicil. p. 489, and by Eschweiler, 1. c.) only P. ^ki- 

 rietina, ascendent, and at length elongated, analogous to the ascendent 

 and elongated states of P. speciosa ; and further attention may well be 

 given to this point on our sea-coast, where the typical forms of both 

 species grow copiously, and often together. 



2. P. PARiETiNA (L., Duf.), Nyl., a, Auct. ; Tuckerm. Synops. Lich. 

 N. E. p. 30, & Lich. Exs. n. 79. On trunks and stones near the sea, 

 and also, more rarely, inland, New England. Bristol, Illinois, Mr. 

 Russell. 



Var. ^. POLTCARPA (Ehrh,), Fr. : microphyllina, suborbicularis, 



VOL. IV. 49 



