i'vi;mfi,i A.] rAKMK.r.irr. -'^7 



ri'cpptaclo ivticiilato-venueosc, the margin incurved, verriicose : 

 spores ()-8na% <•,(»! () -I!) inm. long, 0,008-11 mm. tliick. — Cromb. 

 .lourn. Bot. 1S7(>, ]>. iJfJO. — I'tinntlia tniihr/i/ora, Lcif^lit. Lich. Fl. 

 ( 1S71) p. 140, ed. :i, p. 1:3:3. J'anitcllii MrMUlunn, Stirt. Grevillca, 

 iii. p. "!'. — Indicated by Xylander (Flora, ISIjit, p. 2!»U) as a variety 

 of P. com pa rata, to which it is closely related. I have therefore 

 retained his specific name in preference to that of Leighton, whose 

 diagnosis of the plant is misleading. 



Distinguished tVoui the preceding by the colour of the medulla. The 

 tliallus is smooth aud luiequal, thin or moderate, often whitish-sorediate 

 at the apices of the lobes, tlie soredia becominsr dark-greyish in age. The 

 reaction of the medulla with K, which is pale yellowish (not "yellowish- 

 brown," Leight. ), is especially seen under the microscope. It is very rarely 

 fertile in this country, the apothecia becoming very large, with the thalline 

 margin obliterated. 



Hnh. f)n rocks and boulders in shady wooded upland districts. — Distr. 

 Local and scarce in X.Wales, the S.W. Highlands, Scotland, and AV. 

 Ireland. — B. M. : Xaunau, Dolgellv, Merionethshire : (ilen Croe and 

 ]3arcaldine, Argyleshire. Askew Wood, Dunkerron, co. Kerry (frt.) ; 

 near Kylemore, co. (xahvay. 



7. P. revoluta Xyl. Bull. Soc. Linn. Xormaiid. ser. 2, iii. (1868) 

 p. 2<)4. — Thallus orbicular, moderate, smoothish, narrowlv siniiato- 

 lobed. glaucous-white or whitish : beneath blackish-fibrillose, at 

 length nearly glabrous, the lobes cucullato-revolute and usually 



tuberculato-sorcdiate at the apices (K+'^^^'"""'*'\ CaCl~j.g^^^^j^,^). 



Apothecia nearly moderate, badio-reddish, the margin entire or 

 obsoletely crenate ; spores 6-SnjE, 0,01 1-lU mm. long, 0,o07-12 

 mm. thick. — Cromb. Grevillea, xv. p. 75. — PanneJia tiliacea var. 

 revohita, Leight. Lich. Fl. p. 1:32, ed. 3, p. 129. Iruhruaria revo- 

 luta, Fl6i-ke,D. Lich. ( 1815 )p. 15. — To this also are referable 7^«/-?*(f?m 

 lavigata var. sabsinaosa, Leight. Lich. Fl. ed. 3, p. 1.2U, and P. tili- 

 aeea var. si(/>J(Fvii/ata Leight. Lich. Fl. p. 132, ed. 3, p. 122. — P. suh- 

 hevir/ata Xyl. is an exotic species, which does not occur in Europe. 

 — Brit. E.rs. : Leight. n. 202 (s. n. P. Forsteri Borr.), n. 357 ; Mudd, 

 n. 68 ; Larb. Lich. Hb. n. 293. 



Distinguished from /'. Itecif/afa by the cucullato-revolute apices of the 

 narrower and more approximate lobes, by the chemical reaction of the 

 medulla with CaCl aloi^e, aud by the larger spores. These characters 

 waiTant us in regarding it as a species, and not as a variety of P. la-ciffaia. 

 The tiiberculose soredia, with which the apices of the lobes are frequently 

 covered, are whitish, becoming in age dark-greyish. In this country it is 

 but very seldom seen in fruit. The spermogoues are as in the former 

 species. 



Hub. On rocks and trees among mosses in maritime and mountainous 

 districts. — Distr. General, but not common in S., W., and X. England ; 

 rarer in S. Scotland and the W. Highlands, as also in W. Ireland ; rare 

 in the Channel Islands. — B. M. : La Coupe, Island of Jersey. St. Leo- 

 nards Forest, Sussex ; Isle of Wight ; near Lyudhurst and Bournemouth, 

 Hampshire ; Ilsham, Torquay, Ullacombe, near Bovey Tracey, and Lvn- 

 ton, Devonshire ; Withiel and Penzance, Cornwall ; Aberdovey, Bar- 



