502 LICHEXACEI. [PERTUSAEIA. 



The yerrucoe, occasionally veiy 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. 



Hah. On rocks in maritime and mountainous districts. — Didr. Rather 

 local in S.W. Eudand, X. 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, Argyleshire; Craig Calliach, Perthshire. Lambay Island, near 

 Cork. 



Form 1. microstictica Cromb. — Thallus sprinkled with short, 

 simple, coucolorous papilla3, brownish at the apices. — Lichen 

 mia-osticticus Sm. Eog. 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 

 papillie, as noticed by Turner and Borrer, /. c, are minute, scattered, 

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

 pression in the crust. 



Sah. 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 

 verruciB sterile, transformed into white, pulverulent soredia. — 

 Yar. ft. variolosa Mudd, Man. (1861) p. 271. — 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. 



Hah. On rocks in maritime districts. — Distr. Very local in X. Wales 

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

 Merionethshire. Barcaldijie, Ai'gyleshire. 



16. P. coccodes Xyl. 3Iem. See. 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 + yellow, then deep rusty red, CaCl — ). 

 Apothecia usually several in scattered subglobose or nodulose 

 verrucae : the ostioles punctiform, black, slightly prominent ; spores 

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

 p. 59. Pertusaria glohidifera var. c. coccodes Mudd, Man. p. 274. 

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

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

 (1798) p. lO'; 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 Lecanont porellu, var. Turneri, is often some- 

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

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

 as if "lomerulose. 



