Parmelia.-] LICHENES. 143 



have the state called P. conoplea by Acharius. On rocks in the site 

 of old woods, intermediate varieties may be traced to 3. the Placodium 

 microphyllum of Hooker. 



6. P. aquila, ACH. Thallus stellate, tawney brown, beneath 

 pale, yet with dark fibres ; the segments multifid, linear, con- 

 vex, flattish, and dilated towards the ends ; buds in flatfish, 

 marginal granulations ; apothecia dark brown ; the border rough, 

 incurved, subcrenate. Ach. L. Un. p. 488. Eng. Bot. t. 982. 

 (the colour bad.) 



On siliceous rocks ; common. 



3. Buds, on thallodal solid podetia. 



7. P. olivacea, ACH. Thallus orbicular, olive-brown, white 

 within, shining, lobes crenate, rough with buds on short solid 

 podetia ; apothecia flattish ; the disk light brown ; the border 

 rough with buds. Ach. L. Un. p. 462. Eng. Bot. #.2180. 



On stones and on trees ; common. 



8. P. conspersa, ACH. Thallus stellate, greenish pale-yellow, 

 with a black edge, smooth ; buds somewhat central, roundish, 

 dark olive, on pale solid podetia ; apothecia central, brown, at 

 length flattish ; the margin irregular. Ach. L. Un. p. 486. Eng. 

 Bot. t. 2097. ' 



On siliceous rocks ; not uncommon. 



9. P. proboscidea. Thallus orbicular glaucous-green when 

 wet, greyish- white when dry, with black fibres beneath ; the 

 lobes wide, flattish, rounded, crenate ; the buds brownish on 

 solid white podetia, each at length admitting a black cilium ; 

 apothecia narrowly stipitate ; the disk concave ; the border and 

 back rough with buds. " Lichen proboscideus, Allioni.ScopoL 

 Flor. Cam" according to Acharius in Lick. Un. p. 459 ? Lichen 

 perforatus. Eng. Bot. t. 2423. Parmelia perforata, Hook. Eng. 

 Fl. v. 5, p. 200. (not of Acharius.} 



On siliceous rocks and on trees, not uncommon ; the apothecia rare, 

 in four or five localities near Dunkerron. The figures of Dillenius 

 t. 20, f. 42, 44, and t. 82, /. 3, as well as specimens from near Boston, 

 North America, sent by Mr. Boott to Dr. Hooker, and most kindly 

 communicated by the latter to me, and which I suppose constitute the 

 true P. perforata of Acharius, differ from the British plant 1, by the 

 thallus being destitute of stipitate buds ; so also the apothecia whose 

 margins are smooth and entire ; 2, by the margins of the thallus being 

 here and there laciniated, but not crenate ; 8, by the lobes being more 

 linear ; 4, beneath, towards the edge, the upper and lower surfaces are 

 nearly of the same colour, but in our plant the inferior surface is 

 brownish-black ; 5, by the greater thickness and toughness of the thal- 

 lus ; 6, by the finely reticulato-rugose upper surface ; 7, by the broad 

 tubular podetia to the apothecia ; whereas, in our plant the podetia are 

 narrow, short, and as it were strangulated ; 8, the cilia of the margin 

 of the thallus are longer and stouter ; 9, the apothecia are marginal, 



