496 LICHENACEI. [PERTTTSAKIA. 



Lich. Br. p. 59 ; Gray, Nat. Arr. i. p. 490 ; Sm. Eng. Fl. v. p. 169. 

 Lichen globuliferus Eng. Bot. t. 2008. Lichenoides candidum et 

 fdrinaceum, scutellis fere planis Dill. Muse. 131, t. 18. f. 11 B. 

 Brit. Exs. : Mudd, n. 263 pro parte. 



The thallus, which usually spreads extensively, is somewhat depressed 

 at the circumference, where it presents zones of various shades, chiefly 

 brown and carneous. The fertile verrucee, of which the form and 

 ultimate development are aptly described by Turner and Borrer, I. c., are 

 not of common occurrence and are usually but few on the same plant. 

 More frequently the verrucse are sterile, plane, with a thickish margin and 

 densely white-sorediate having a lecanoroid appearance. In this abortive 

 condition of the apothecia, which at times occurs on the same plant as 

 their normal state, it is form discoidea Crornb. Grevillea, xix. p. 59; 

 Lichen discoideus Eng. Bot. t. 1714 ; Variolaria discoidea Turn. & Bon-. 

 Lich. Br. p. 61, Sm. Eng. Fl. v. p. 168, Tayl. in Mack. Fl. Hib. ii. p. 112, 

 Dill. /. c. f. 11 C. 



Hub. On trunks of old trees in wooded maritime and upland districts. 

 Distr. General and common where it occurs in Great Britain ; appa- 

 rently rare in Ireland. B. M. : Yarmouth, Norfolk : Epping Forest, 

 Essex ; Penshurst, Kent ; Shiere, Surrey ; St. Leonard's Forest and 

 Danny, Sussex ; New Forest, Hants ; Chudleigh and Beckey Falls, 

 S. Devon ; Boconnoc and near Withiel, Cornwall ; Savernake Forest, 

 Wilts; Cirencester, Gloucestershire ; Madingley, Cambridgeshire; Charn- 

 wood Forest, Leicestershire ; Malvern, Worcestershire ; Lambeth, S. 

 W r ales; Barmouth, Merionethshire; Island of Anglesea; Craig-y-Rhiw 

 and Haughmond Hill, Shropshire ; near Ayton, Cleveland, Yorkshire ; 

 Teesdale, Durham. Helensburgh, Dumbartonshire ; Inverary and by 

 Loch . Creran, Argyleshire ; Craigforth, Stirling ; Glen Lochay, Killin, 

 and Blaeberry Hill, near Perth, Perthshire ; Murtle, near Aberdeen ; by 

 Loch Linnhe, Inverness-shire. Castlemartyr and Macroom demesne, 

 co. Cork ; Ashley Park, near Galway. 



8. P. ophthalmiza Nyl. Flora, 1865, p. 354. Thallus effuse, 

 thin, smoothish, or slightly rugoso-unequal, greyish (K , CaCl ) ; 

 fertile verrucas small, more or less crowded. Apothecia 1, rarely 

 2-3 in each verruca, lecanoroid, blackish, crowned with a rugose or 

 subleprose thalloid margin; spores 0,160-205 mm. long, 0,080- 

 100 mm. thick. Carroll, Journ. Bot. 1866, p. 23 ; Leight. Lich. 

 Fl. p. 242, ed. 3, p. 233. P. globulifera subsp. ophthalmiza Cromb. 

 Lich. Brit. p. 59; var. ophthalmiza Nyl. Lich.Scand. (1861) p. 180. 



Well distinguished from the preceding, to which it has a superficial 

 resemblance, by the form of the fructification. It spreads extensively, 

 though interruptedly, over the substratum with no visible circumferential 

 line. The fertile verrucse are usually numerous, at times almost oblite- 

 rating the rest of the thallus. 



Hab. On the trunks of aged pines in an upland district. Distr. Only 

 sparingly in the S.W. Highlands of Scotland. B. M. : Glen Falloch, 

 and Black Wood, Rannoch, Perthshire. 



9. P. amara Nyl. Flora, 1873, p. 22. Thallus determinate, 

 rugoso-rimose, unequal, subpulverulent, greyish-white, brown and 

 zonate at the circumference (K , CaCl ). Apothecia white- 



