506 LICHEIfACEr. [P£RTCSAEIA. 



In general appearance not unlike P. communis, Liit differs in the colour 

 of the thallus, the foim of the apothecia, and more especially in the 8- 

 spored thecte. The thallus is at times widely expanded, and is often 

 nlmost entirely covered with the numerous crowded venaicfe, which 

 trnm mutual pressure become much deformed. By the confluence of the 

 ostiola when there are more than one in the same ven-uca, the apothecia 

 assume a discoid aspect with a thick, inflexed, rugoso-crenate thalloid 

 margin. The spermogones are not unfrequent, with spermatid 0,01.j-23 

 mm. long, 0,000o mm. thick. 



Hah. On trunks of trees, chiefly in forests and large woods, from 

 maritime to upland districts. — Disfr. General and not uncommon in 

 England; apparently rare in Scotland and Ireland. — B. M. : Sotterly, 

 Ugley, and Yarmouth, Suffolk ; Epping and Hainault Forests, Essex; 

 Pen.shurst, Kent; St. Leonard's Forest, Sussex; New Forest, Hants; 

 near Totnes and Lustleigh, S. Devon ; Bocconoc and Withiel, Cornwall ; 

 Cliarnwood Forest, Leicestershire ; Dolgelly and Aberdovey, Merioneth- 

 shire ; Trefi-iw, Denbighshire ; near Conway, Carnarvonshire ; Oswestry 

 and Llauyblodwell, Shropshire ; Ingleby Park, Cleveland, Yorkshii-e ; 

 Teesdale Forest, Durham ; Keswick, Cumberland. Barcaldine, Argyle- 

 shire ; Craig Calliach and Blair Athole, Perthshu-e ; Durris, Kincardine- 

 shire ; Craig Clunv, Braemar, Aberdeenshire. Castlebernard Park, co. 

 Cork ; Dinish, Killarney, co. Kerry. 



Form 1. camea Fr. Lich. Eur. (1831) p. 424. — Thallus as in the 

 type. Apothecia with the disc protruded, tumid and flesh-coloured. 

 — Cromb. Grevillea, xis. p. 59. — Tlielotrema 7ii/inenium yar. y. car- 

 neum Turn. & Borr. Lich. Br. (1849) p. 185. 



E^ddently a monstrosity with abortive fructification. Though the 

 thallus is said by Turner and Borrer to be thin and tilmv on the bark of 

 cherry and holly, yet when growing on beeches it is quite as in the type. 



Hub. On the bark of trees in wooded upland tracts. — Distr. Very local 

 and scarce in S. England.— B. M. : New Forest, Hants; Toy's Hill, 

 Canterbury, Kent. 



Form 2. sparsilis Xyl. ex Leight. Lich. Fl. ed. 3, (1879) p. 232. 

 — Thallus scanty, whitish-yellow, the fertile verrucoe few, distantly 

 scattered ; otherwise as in the type. 



A rather singular condition, depending probably upon the habitat. In 

 the few fragments seen the thallus is little visible. 



Hob. On moist shady rocks in an upland situation. — Distr. Only very 

 sparingly in W. Ireland. — B. M. : Lough Inagli, Connemara, co. Galway. 



Yar. p. glabrescens Xyl. Flora, 1873, p. 71. — Thallus thin, 

 smoothish or slightly rugulose, yellowish-grev or greyish-green. 

 Apothecia with the epithecium subrimose, blackish. — Cromb. Gre- 

 Tillea, xix. p. 59. 



Apparently a good variety characterized by the thinner, smoother 

 thallus and the form of the epithecium. In the single British specimen 

 the fertile verructe are mostly somewhat scattered. 



Hah. On the trunks of holly in a mountainous district. — Distr. Only 

 in the S.AV. Highlands of Scotland, though probably to be detected else- 

 where. — B. M. : Barcaldine, Argvleshire. 



