494 LICHEN ACEI. [PERTTJSARA. 



A well-marked species readily recognized, even when sterile, by the 

 peculiar thalline papillae. The apothecia, recently described by Nylander, 

 from plants gathered 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 

 (fide Nyl.). 



Hob. On quartzose and schistose rocks in a mountainous region. Distr. 

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



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

 minate, rugose, areolato-rimose, greyish- white (K ~ el]ow thpn 



saffron-orange). Apothecia at first innate in the areolse, 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. 



Nylander I. c. says that this is subsimilar to P. dealbafa, 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 verrucse are numerous and here and there- 

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

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



Hab. On schistose rocks in a mountainous region. Distr. Extremely 

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



6. P. multipuncta Nyl. Not. Sallsk.pro F. ct Fl.Fenn.Fdrh. xi. 

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

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

 i'ertile verrucee small, prominent, usually white-sorediate (K , 

 CaCl ,1 + dark-bluish). Apothecia usually numerous in each 

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

 oblong or lineari-oblong, 0,106-140 mm. long, 0,028-68 mm. thick. 

 Cromb. Grevillea, xix. p. 59. Pertusuria multipunctata Leight. 

 Lich. Fl. p. 236, ed. 3, p. 226. P. globulifera /3. multipunctata 

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

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

 & Borr. Lich. Br. p. 73 ; Gray, Nat. Arr. i. p. 490 ; Sm. Eng. Fl. v. 

 p. 170. Lichen multipunctus, Eng. Bot. t. 2061. A saxicolous 

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

 p. 474 ; Lich. Fl. p. 245, ed. 3, p. 236 (cfr. Nyl. Flora, 1883, 

 p. 534). Brit. Exs. : Mudd, n. 262. 



Has often externally the aspect of some PMyctis, as noticed by Th. M. 

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

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

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

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

 only visible at times a very faint yellow tinge immediately passing into 

 brown. 



