Parmelia.] L1CHENES. 203 



Summits of the Highland mountains, growing on rocks. On Ben- 

 Nevis, plentiful. 



24. P. encdusta, Ach. (encaustic Parmelia); thallus stellated 

 brownish-grey dotted with black the segments deeply and much 

 divided linear tumid here and there constricted convex on both 

 sides, black uneven and naked beneath, apothecia red-brown 

 with a somewhat crenulated border. — Ach. Syn. p. 206. — 

 Lichen encaustns, Sm. in Linn. Trans, v. 1. p. 83. t. 4. f. 6. 

 E. Bot. t. 2049. 



Plentiful on rocks, on the summit of Ben-Nevis, where it was first 

 detected by Dr. Stuart. 



25. P. dquila, Ach. (sun-burnt Parmelia); thallus orbicular 

 tawny-brown very much divided into numerous imbricated 

 crowded branched narrow linear segments with their margins 

 inflexed, black and shaggy beneath, apothecia dark-brown with 

 an incurved and cremated border — Ach. Syn. p. 205. — Lichen 

 aquilus, Ach. Prodr. — E. Bot. t. 982. — L. fuscus, Huds — 

 ])ichs. — L. puttus, Light/. — L. obscurus, With. — Bill. Muse. 

 t. 24. /. 69. 



On rocks, in various parts of Britain; yet not very general: most 

 abundant on the borders of Devon and Cornwall. — Closely applied to 

 the rock on which it grows, and remarkable for its tawny-brown hue and 

 the very numerous and much divided narrow segments of the thallus. 



26. P. aleuritcs, Ach. (mealy spreading Parmelia); thallus 

 orbicular continuous rugged greyish-white mealy lobed in the 

 circumference sinuated crisped and notched, beneath of the 

 same colour with blackish fibres, apothecia elevated plane red- 

 (li>h-brown with an inflexed crenulated and pulverulent border. 

 — Ach. Syn. p. 208. — Lichen aleurites, Ach. Prodr. — E. Bot. 

 t. 858.— L. diffusus, Bichs. Cr. Ease. 3. ;;. 17. t. 9./ 6. 



Trunks of trees, posts, rail.-,, &C. On the bark of firs in the north, 

 frequent. 



27. P. (inihtgiia, Aeh. (yellowish pouxb ry Parmelia); thallus 



stellated pale yellow-green smooth bearing powdery warts the 

 segments Linear appressed plane dichotomous somewhat trunca- 

 ted, beneath brownish-black and fibrillose, apothecia near the 

 centre email nearly plane brown their border entire — Ach. Syn. 

 />. 208. Hook. 11. Sot. /'. 11. j>. 55. — Psora ambiaita, ffoffin. 

 PL Lich.f. -2 — 1, andt 42./ 2, 



Trunk/ of Fir-trees in tin- Highlands, especially in the northern 

 I Kinnordy, Forfarshire:— always barren. 



2 . I*. rinudaOi Ach. (sinuous imbricated Parmelia); thallni 

 orbicular imbricated smooth of a sulphureous-grey ii> segments 

 pinnatifhl with dilated cloren lobes and ciircular sinuses, be n ea th 

 black with dense fibres, apothecia brown with a thin smooth 



entire border. Sw.—.lr.',. Syn, />. i't»7.— /. 1 



