PERTUSABRIA | PERTUSARIACE 365 
Shiere, Surrey ; Epping Forest, Hadleigh and Hockley Woods, Essex ; 
Burnham Beeches, Bucks; Dolgelly and Barmouth, Merioneth. 
14. P. pertusa Dalla Torre & Sarnth. Die Flecht. Tirol, p. 309 
(1902).—Thallus determinate, warted-areolate or wrinkled, thick, 
or sometimes flat and thinnish, especially towards the concentri- 
cally marked margin, the fertile warts or verruce large and 
prominent, irregularly sub-globose, generally crowded, though 
sometimes thinly scattered, greyish or greenish-grey (K Pyclowish 
CaCl —). Apothecia one or several in each verruca, punctiform, 
the disc minute, slightly depressed, blackish ; epithecium K + 
violet ; paraphyses slender; spores 2 in the ascus (sometimes 
1 or 3 or 4), 130-205 p long, 45-80 » thick; hymenial gelatine 
round the asci persistently blue with iodine.—P. communis DC. 
Fl. Fr. ii. p. 320 (1805) (incl. f. rupestris) ; Hook. in Sm. Engl. 
Fl. v. p. 160; Turn. & Borr. Lich. Brit. p. 196 (incl. var. 
rupestris) ; Leight. Angioc. Lich. p. 27 & Lich. Fl. v. p. 238; 
ed. 3, p. 229 (incl. f£. rupestris); Mudd Man. p. 275; Cromb. 
Lich. Brit. p. 58 & Monogr. i. p. 499 (incl. f. rupestris). 
P. rupestris Scher. Enum. p. 227 (1850); Mudd Man. p. 272 
(incl. var. areolata? (non Clem.)). Lichenoides verrucosum et 
rugosum, cinereum, glabrum Dill. Hist. Muse. p. 128, t. 18, fig. 9 
(1741). Lichen pertusus L. Mant. p. 131 (1767); Lightf. FI. 
Scot. ii. p. 802 ; Huds. Fl. Angl. ed. 2, p. 525 ; With. Arr. ed. 3, 
iv. p. 15; Engl. Bot. t. 677. Porina pertusa Ach. Lich. Univ. 
p- 308 (1810) ; 8. F. Gray Nat. Arr. i. p. 495; Hook. Fl. Scot. ii. 
p- 45; Grev. Fl. Edin. p. 354; Tayl. in Mackay FI. Hib. ii. 
p. 102. 
Ezxsicc. Bohl. n. 54; Johns. nos. 278, 279, 422 (Brit. Mus. 
set as P. pustulata); Leight. n. 71 (Brit. Mus. set as P. fallaz) ; 
Mudd nos. 259 (£. rupestris), 264. 
One of the commonest British lichens, easily known by the 
prominent verruce. The apothecia vary from one to many in each 
verruca, the narrowed discs are generally dark coloured, but may be 
whitish in shade conditions (f. lewcostoma Scher. Enum. p. 229 
(1850) ) when there is also no reaction of the epithecium with K. 
The reactions of both thallus and apothecia, the latter characteristic 
of several other species, are sometimes rather faint. The thallus is 
frequently the host of Sphinctrina turbinata. Form rupestris differs 
only in habitat, it is rather uncommon. 
Hab. On the trunks of old trees, rarely on palings or on rocks in 
lowland and upland regions.—Distr. General in the British Isles.— 
B. M. Sark; Guernsey; Withiel, Cornwall; near Bovey Tracey and 
Lustleigh, Devon; Appuldurcombe, I. of Wight; New Forest, Hants ; 
near Hastings, near Battle, St. Leonard’s Forest, Ardingly, Henfield 
and Offham, Sussex; Penshurst, Kent; Shiere, Surrey; Hockley 
Wood, Hatfield Peverel and Epping Forest, Essex ; near Buckingham ; 
Cirencester, Gloucestershire ; Broadwas and near Malvern, Worcester- 
shire ; Twycross and Gopsall Park, Leicester ; Hafod, Cardiganshire ; 
Barmouth and Dolgelly, Merioneth; Buildwas, Shropshire; Bettws- 
y-Coed, Denbighshire; near Conway, Carnarvonshire; Anglesea; 
