402 86. Polychid. 3. HOMOTHALAME^. Pl.cell.aph. 
Lichen byssinus, Wahl. FI. Lapp. 442. 
Lichen tenuissimus, Dickson Crypt. 1, 12. 
Parmelia tenuissima, Achar. Melh. Lich. 244. 
Coliema byssinutn, Hoffm. Germ. 105. 
Coliema tenuissimum, Achar. Lich. Univ. 659. 
On gravel-banks, walls, and mosses. 
3. Polycfudium Schraderi. Schrader s poly chide. 
Thallus rather tufted ; jaggs linear, flat, irregularly un- 
divided, wrinkled, blunt; edges turned over, slightly cre- 
nate; apothecia scattered, colour of the thallus. 
Lichen Schraderi, Bern, in Schrad. Journ. 1799, 22. 
Parmelia Schraderi, Achar. Meth. Lich. 24 3. 
Coliema Schraderi, Achar. Lich. Univ. 658. 
On rocks among mosses. 
4. Polychidium muscicolum. Moss poly chide. 
Thallus shrublike, cushioned, brownish ; branches cylin- 
drical, rather upright, bent, knotted, nearly even-topped*, 
bluntish ; apothecia nearly terminal, flat, brown, edged. 
Lichen Muscieola, Swartz in N. Act. Ups. 4, 248 ; Dicks. Crypt. 2, 8. 
Parmelia muscieola, Achar. Meth. Lich. 244. 
Coliema Muscieola, Achar. Lich. Univ. 660. 
On the ground, and mountains among moss. 
6. Polychidium velutinvm . Velvet poly chide. 
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, Lightf. Scot. 894. 
Lichen velulinus, Achar. Prod. 218. 
Parmelia pannosa, Achar. Meth. Lich. 246. 
Conferva pannosa, Web. el Mohr Reise, 105. 
Coliema nigrum ? Hoffm. Germ. 103. 
Coliema pannosum, Achar. Lich. Univ. 660, not of Hoffman. 
On rocks and mountains amon<>- mosses. 
6. Polychidium spongiosum. Spongy poly chide. 
Thallus dark green ; jaggs aggregated, branched, gra- 
nular, cylindrical, blunt ; apothecia scattered, hollow, 
brown ; outside spongy, pale ; edge upright, thin. 
Lichen spongiosus, Engl. Dot. 1374. 
Coliema spongiosum, Achar. Lichen. Univ. 661. 
Durham; perennial. 
