502 . LICHENACEI. [PERTUSARIA. 



The verrucae, occasionally very tumid, vary considerably according to the 

 number of the ostioles. 'These are usually 1, but sometimes 3, 4, 5, or 

 even more, appearing like minute, blackish subpapillate dots. 



Hob. On rocks in maritime and mountainous districts. Distr. Rather 

 local in S.W. England, N. Wales, the S.W. Highlands, and the S. 

 Grampians, Scotland, as also in S. Ireland. B. M. : Pentire, Lamorna, 

 near Penzance, Cornwall ; Barmouth and near Dolgelly, Merionethshire. 

 Appin, Argvleshire; Craig Calliach, Perthshire. Lambay Island, near 

 Cork. 



Form 1. microstictica Cromb. Thallus sprinkled with short, 

 simple, concolorous papillae, brownish at the apices. Lichen 

 microsticticus Sm. Eng. Bot. xxxii. (1811) t. 2243. Isidium 

 microsticticum Turn. & Borr. Lich. Br. p. 94 : Hook. Fl. Scot. ii. 

 p. 66; Gray, Nat. Arr. i. p. 774 ; Sm. Eng. Fl. v. p. 231. Brit. 

 Exs. : Leight. n. 342. 



A sterile condition analogous to form Westringii of P. concreta. The 

 papillae, as noticed by Turner and Borrer, I. c., are minute, scattered, 

 rarely confluent, brittle, and when abraded leave a minute white im- 

 pression in the crust. 



Hab. On rocks in maritime and mountainous districts. Distr. Spar- 

 ingly in the Channel Islands, N. Wales, and S.W. Ireland. 



Form 2. variolosa Cromb. Grevillea, xix. p. 59. Thalliue 

 verrucae sterile, transformed into white, pulverulent soredia. 

 Var. ft. variolosa Mudd, Man. (1861) p. 27L Brit. Exs.: Leight. 

 n. 341. 



Though looking as if distinct, it is only one of those variolarioid con- 

 ditions so common in the plants of this genus. 



Hab. On rocks in maritime districts. Distr. Very local in N. Wales 

 and the S.AV. Highlands of Scotland. B. M. : Barmouth and Dolgelly, 

 Merionethshire. Barcaldine, Argyleshire. 



16. P. coccodes Nyl. Mem. Soc. Cherb. t. v. (1857) p. 146. 

 Thallus determinate or effuse, unequal, subleprose, rimulose or 

 rimose, at times verruculose, whitish, often limited by a dark line 

 at the circumference (K-f- yellow, then deep rusty red, CaCl ). 

 Apothecia usually several in scattered subglobose or nodulose 

 verruca? : the ostioles punctiform, black, slightly prominent ; spores 

 0,115-140 mm. long, 0,040-60 mm. thick. Cromb. Lich. Brit, 

 p. 59. Pertusaria globulifera var. 3. coccodes Mudd, Man. p. 274. 

 Isidium coccodes Turn. & Borr. Lich. Br. p. 89 ; Sm. Eng. Fl. v. 

 p. 230 ; Gray, Nat. Arr. i. p. 412. Lichen coccodes Ach. Prodr 

 (1798) p. 10; Eng. Bot. t. 1511. 



A distinct species, though by some authors mixed up with the 

 preceding, from which, apart from the habitat, it is sufficiently separated 

 by the characters given. The sterile thallus, which, when more leprose, 

 is apt to be mistaken for Lecanom porella, var. Turner i, is often some- 

 what isidioid with the isidia cylindrical, short and simplish. When 

 fertile, as it rarely is in the British specimens, the verrucae are at times 

 as if glomerulose. 



