402 86. Polychid. 3. HOMOTHALAMEZ:, Pl. cell. aph. 
Lichen byssinus, Wahl. Fl. Lapp. 442. 
Lichen tenuissimus, Dickson Crypt. 1, 12. 
Parmelia tenuissima, Achar. Meth, Lich, 244. 
Collema byssinum, Zfoffm. Germ. 105. 
Coliema tenuissimum, Achar. Lich. Univ. 659. 
On gravel-banks, walls, and mosses. 
3. Polychidium Schraderi. Schrader’s polychide. 
Thallus rather tufted; jaggs linear, fiat, irregularly un- 
divided, wrinkled, blunt; edges turned over, slightly cre- 
nate; apothccia scattered, colour of the thallus. 
Lichen Schraderi, Bern. in Schrad. Journ. WSIS). ce) 
Parmelia Schraderi, Achar. Meth. Lich. 243. 
Collema Schraderi, Achar. Lich. Univ. 658. 
On rocks among MOsses. 
4. Polychidiun: muscicolum. Moss polychide. 
Thaillus shrublike, cushioned, brownish; lranches cylin- 
drical, rather upright, bent, knotted, nearly even-topped, 
bluntish ; upothecia nearly terminal, flat, brown, edged. 
Lichen Muscicola, Swartz in N. dct. Ups. 4,248; Dicks. Crypt. 2, 8. 
Parmelia muscicola, Achar. Meth. Lich. 244. 
Collema Muscicela, Acker. Lich. Univ. 660. 
On the ground, and mountains among moss. 
5. Polychidium velutinum. Velvet polychide. 
Thallus cushioned, black ; jaggs cylindrical, very tender, 
scarcely branched, bent, interwoven, even-topped; apo- 
thecia rather concave, minute, colour of the thallus, pressed 
close, edged. 
Lichen exilis, Light/. Scot. 894. 
Lichen velutinus, 4char. Prod. 248. 
Parmelia panneosa, char. Meth, Lich. 246. 
Conferva pannosa, Web. et Moukr fteise, 105. 
Collema nigrum? Hoffm. Germ. 103. 
Collema pannosum, Achar. Lich. Univ. 660, not of Hoffman. 
On rocks and mountains among mosses. 
6. Polychidium spongiosum. Spongy polychide. 
Thallus dark green; jaggs aggregated, branched, gra- 
nular, cylindrical, biunt; apothecta scattered, hollow, 
brown; outside spongy, pale; edge upright, thin. 
Lichen spongiosus, Engl. Bot. 1374. ; 
Collema spongiosum, Achar. Lichen. Univ, 661. 
Durham; perennial. 
