74 CYCLOCARPINEX [PERTUSARIA 
Sommerfelt in Fl. Lapp. Suppl. p. 85 (1826) as Lecidea carneolutea 
(non Turn.) with the name Lecidea protuberans Sommerf. in litt. in 
the.synonymy. The first of these names was based on error, the second 
is a syonym which has been republished by Th. Fries in Lich. Arct. 
p. 102 (1860) as Lecanora protuberans and in Lich. Scand. p. 305 as 
Pertusaria protuberans. Nylander’s is the first authentic name. 
Hab. On the bark of alders in mountainous regions; recorded by 
Crombie from Appin, Argyll. 
28. P. Wulfenii DC. FI. Fr. ii. p. 320 (1805).—Thallus effuse 
or determinate, thin and membranaceous or becoming thickish, 
wrinkled or areolate-cracked, whitish- or yellowish-grey (K+ 
yellowish, K(CaCl) + orange-yellow). Fertile verrucee numerous, 
sometimes confiuent, of irregular form, with one or several 
apothecia, at first with punctiform ostioles, then enlarging to a 
dark-coloured (more rarely flesh-coloured) disc, with an irregular 
tumid crenate margin; epithecium K + violet; spores usually 
8 in the ascus (sometimes fewer), 58-115 p long, 28-50 p thick.— 
Cromb. Lich. Brit. p. 60 & Monogr. i. p. 505 (incl. var. glabrescens). 
P. fallax Hook. in Sm. Engl. Fl. v. p. 160 (1833); Leight. 
Angioc. Lich. p. 29, t. 10, fig. 2 (1851) & Lich. Fl. p. 240 pro 
parte; ed. 3, p. 231; Mudd Man. p. 276. Lichenoides verrucosum 
et rugosum, cinereum, glabrum Dill. Hist. Muse. p. 128, t. 18, 
fig. 9 pro parte (1741). Lichen hymenius Ach. Lich. Suec. Prodr. 
p. 80 (1798)? Engl. Bot. t. 1731. Thelotrema hymenium Ach. 
Meth. Lich. p. 133 (1803)? Turn. & Borr. Lich. Brit. p. 185 
pro parte. Verrucaria fallax Pers. ex Ach. Meth. Lich. p. 133 
(1803)? nomen nudum. Porina fallax Ach. Syn. Lich. p. 110 
(1814); Tayl. in Mackay Fl. Hib. ii. p. 102. P. hymenea 
S. F. Gray Nat. Arr. i. p. 495 (1821). 
Exsicc. Bohl. n. 100 ; Johns. nos. 154, 166 (as var. diffracta) ; 
Leight. n. 71 ; Mudd n. 266. 
Similar to P. pertusa in habitat and in the peculiar reaction of 
the epithecium with potash, but differing in the wide open disc, and 
in the number of the spores; these vary considerably in size according 
to the number in the ascus and to the stage of maturity; the sizes 
recorded in British Floras are too small. The thallus varies from a 
thin film with prominent verruce (var.*glabrescens Nyl. in Bull. Soc. 
Linn. Norm. sér. 2, vi. p. 290 (1872)), to a thick coarsely cracked- 
areolate crust (var. diffracta Johns. exs. n. 156). There are numerous 
intermediate stages, and they evidently depend on the type of bark 
on which the plant grows. Though normally a corticolous species, it 
may stray to other substrata; a specimen from a stone and mortar 
wall, collected at Belclare, Mayo, is typical P. Wulfenii, and quite 
distinct from var. rupicola (P, sulphurea), and with a more developed 
thallus than form sparsilis. According to Th. Fries (Lich. Scand. 
p. 317), Lichen hymenius Ach. more probably represents a form of 
P. leioplaca, while the original Verrucaria fallax Pers. is synonymous 
with P. pustulata (tom. cit. p. 313). 
Hab. On trunks of trees in parks and woods (rarely saxicolous). 
—Distr, General and fairly common in the wooded districts of the 
