494 LICHEXACEI. [PERTUSAKA. 



A Tvell-marlied species readily recognized, even when sterile, by the 

 peculiar thalline papillae. The apothecia, recentW described by Isylander, 

 from plants pathered in the E. Pyrenees, are seldom rightly developed in 

 the few British specimens. The spermogones, also rare in these, have 

 the spermatia bacillar, about 0,004-5 mm. long, scarcely 0,001 mm. thick 



Hab. On quartzose and schistose rocks in a mountainous region. — Distr. 

 Seen only sparingly from jN. Wales. — B. M. : Barmouth, Merionethshire. 



5. P. monogona Xyl. Flora, 1873, p. 71. — Thallus subdeter- 



minate, rugose, areolato-rimose, greyish-white (K ~ n (.i 



saifron-orange). Apothecia at first innate in the areolae, then 

 somewhat prominent, the thalline margin entire or subcrenate ; 

 epithecium dilated, brownish, uneven, white-pulverulent ; spores 

 oblongo-ellipsoid, 0,150-235 mm. long, 0, 070-80 mm. thick. — 

 Cromb. Grevillea, xix. p. 59. 



Kylander /. c. says that this is subsimilar to P. dealhafa, from which it 

 at once differs in the monospored theca?. The other characters given 

 sufficiently distinguish it from this and other British Pertusarias. In 

 our specimens the fertile verrucae are numerous and here and there 

 crowded. The spermogones are not infrequent, with spermatia about 0,004 

 mm. long, nearly 0,001 mm. thick. 



Sah. On schistose rocks in a mountainous region.- — Distr. Extremely 

 local and scarce in N. "Wales — B. M. : Cader Idris, Merionethshire. 



6. P. multipuncta Xyl. Xot. Sallsk. pro F. ct Fl. Fenn. Forli. xi. 

 (1870) p. 185. — Thallus determinate or subdeterminate, thinuish, 

 granulato- or rugoso-unequal, rimose, whitish or greyish-white ; 

 fertile verrucae small, prominent, usually white-sorediate (K — , 

 CaCl — , I -|- dark-bluish). Apothecia usuallj- numerous in each 

 verruca, pale or blackish, csesio-pruinose, at length naked ; spores 

 oblong or lineari-obloug, 0,106—140 mm. long, 0,0u8-68 mm. thick. 

 — Cromb. Grevillea, xix. p. 59. — Pertusuria vwltipanctata Leight. 

 Lich. Fl. p. 1^36, ed. 3, p. 226. P. glohulifera fi. muUipunctata 

 Mudd, Man. p. 274 ; Cromb. Lich. Brit. p. 59. VarioJaria multi- 

 ■pumta Turn. Trans. Linn. Soc. ix. (1808) p. 137, t. 10. f. 1 ; Turn. 

 «& Borr. Lich. Br. p. 73 ; Gray, iS'at. Arr. i. p. 490 ; !Sm. Eng. Fl. v, 

 p. 170. Lichen multijnti^ctus, Eng. Bot. t. 2061. — A saxicolous 

 state is Pertusaria suhlactea Leight. Ann. Mag. Nat. Hist. 1870, vi. 

 p. 474; Lich. Fl. p. 245, ed. 3, p. 236 (ifr. Isyl. Flora, 1883, 

 p. 534).— 5n«. Exs. : Mudd, n. 262. 



lias often externally the aspect of some Phlyctis, as noticed by Th. M. 

 Fries (Lich. Scand. p. 309). From the other species of the genus it is 

 well separated by the more elongate spores. The verrucae are usually 

 very numerous, though distinct, each with from 1 to 12 apothecia. The 

 thaUine reaction with K is erroneously given by Leighton, there being 

 only visible at times a "\ery faint yellow tinge immediately passing into 

 brown. 



