ACOTYLEDONS. LICHENS. Cctrarla. 57 



HAB. Trunks of old trees and pales, but not very common, Lightf. 



'1. B. flavicans, thallus yellow naked, segments dichotomously 

 hranehed slightly compressed attenuate divaricated compli- 

 cated, apothecia scattered their disk plane orange 'red their 

 margin entire naked. Ach. Syn. Lick. p. 225. Lichen flavi- 

 cans, E. B. f. 21 13. Lichen vulpinus, Lightf. p. 896. 



HAB. Trunks of old trees, but not common. On the ground on the 

 Craig of Ailsa, Lightf. 



19. CETRARIA. 



Universal receptacle between cartilaginous and membranaceous, 

 ascending or spreading, lobed and laciniated, on each side 

 smooth and naked. Partial recept. scutelliform, obliquely 

 adnate with the margin of the thallus, the lower portion being 

 free (not united with the thallus), the upper sessile, the disk 

 coloured, plano-concave, with a margin formed of the thallus 

 and inflexed. 



1. C- juniperina, thallus pale yellow very yellow bencoth, the 

 segments plane ascending erose crenate and crisped, apothecia 

 elevated their disk brown the margin crenulated. Ach. Syn. 

 Lick. p. 226. 



/3. pinastri, thallus with the segments depressed the lobes 

 rounded crenate the margins crisped pulverulent and very 

 yellow. Lichen pinastri, E. B. t. 2111. Lichen juniper inus, 

 'Lightf. p. 836. 



HAB. Trunks and branches of elms and many other trees, common. 

 Fir trees about Aviemore and at Kinnordy Kerrie-muir, Hook. 

 Never, I believe, found with apothecia in Britain ; though not rare 

 in that state in Switzerland. 



2. C. sepincola, thallus olive-brown paler beneath the segments 

 plane ascending lobed waved subcrenate, apothecia elevated 

 of the same colour their margin rugose and crenulate. Ach. 

 Syn. Lich. p. 227. Lichen sepincola,' E. B. t. 2386. 



HAB. On stones in the Scotch mountains, according to Mr. Dickson. 

 I have never seen it in any country but on wood. On fir trees at 

 Kinnordy Kerrie-muir, Mr. Lyell and Hook. Fructification very rare. 



3. C. glauca, thallus glaucous somewhat shining sinuated and 

 lobed brown beneath, the segments cut and jagged curled 

 ascending, apothecia elevated chesnut brown their margin 

 wrinkled. Ach. Sy?i. Lich. p. 227. Lichen glaucus, Lightf. 

 p. 838. E.B.t. 1066. 



|3. fallaXy thallus white on each side, or with occasional black 

 spots beneath. L. fallax, E. B. t. 23/3. 



HAB. On the ground in heathy places, on rocks and trees, not un- 

 common. /3. On the ground near the cascade at Invcrary. 



4. C. nivalisj thallus sulphur-coloured orange at the base pitted 



