510 LICHEXACEI. [PERTUSARIA. 



Form hexaspora Xyl. Lich. Scand. (1861) p. 182. — Spores 

 usually 6n8e, 0,u3S-86 mm. long, 0,025-38 mm. thick. Otherwise 

 as in the type. 



Differs merely in the thecae being generally 6-spored, though in the 

 same apothecium they are occasionally 4-spored. Nylander (/. c.) says 

 the spores are rarely 3nse, which is not the case in our specimens. 



Sab. On trunks of trees in maritime and upland wooded situations. 

 — Disir. Only a few localities in S. and W. England. — B. M. : Shanklin, 

 Isle of Wight ; near Lyndhurst, New Forest, Hants ; Ullacombe, Bovey 

 Tracey, S. Devon ; Oakley Park, Cirencester, Gloucestershire. 



29. P. glomerata Schaer. Spicil. (1823) p. 66.— Thallus effuse, 

 thin, interruptedly plicato-verrucose, white or yellow-cream-coloured, 

 the fertile vcrrucae subglobose, conglomerate (K-|- bright yellow, 

 then cinnabar-red, CaCl— ). Apothecia usually soHtarj-, the ostioles 

 punctiform or slightly dilated, generally somewhat prominent, 

 blackish; spores 0,072-125 mm. long, 0,02':;-44 mm. thick. — 

 Mudd, Man. p. 277 ; Cromb. Lich. Brit. p. 60 ; Leight. Lich. Fl. 

 p. 237, ed, 3, p. 227. — Lichen glomeratus Schleich. PI. Crypt. Cent, 

 iii. (1807) n. 11, fide Ach. Lich. Lniv. p. 310 (sub Porhia). Per- 

 tusaria r/lomulifera (Borr.) Leight. Lich. Fl. p. 2-13, ed. 3, p. 234, 

 Angio. Lich. p. 30, t. 11. f. 2, is only an old dealbate state in which 

 the reaction with K is absent. 



An alpine plant well distinguished from its allies by the characters 

 given and by the habitat. The thallus, scarcely contiguous, is itself 

 white (K — ), as noted by Th. M. Fries (Lich. Scand. p. 315) ; but the 

 fertile verrucae, which are occasionally 2-3 concrescent, are more or less 

 ochroleucous. The few British specimens are well fertile, the ostioles 

 being at times two and often subpapillate. The spermogones, rarely 

 present, have the spermatia aciculari-fusiform, 0,008-11 mm. long, 

 0,0005 mm. thick (fideyyl). 



Sab. Incrusting dead mosses at high altitudes on mountains. — Distr. 

 Local and scarce on the S. Grampians, Scotland. — B. M. : Craig CaUiach 

 and Ben Lawers, Perthshire. 



30. P. xanthostoma Fr. Lich. Eur. (1S31) p. 427.— Thallus 

 effuse, thin, smooth, milk-white, the fertile verrucae elevated, 

 depresso-subglobose (K — , CaCl — ). Apothecia punctiform, usual!}- 

 1-2 in each verruca ; the ostioles depressed, pale or pale-yellowish ; 

 spores ellipsoid or ellipsoideo-oblong, 0,060-76 mm. long, 0,034-40 

 mm. thick. — Cromb. Journ. Bot. Ife75, p. 141 ; Leight. Lich. Fl. 

 ed. 3, p. 235. — Porina xanthostoma Somm. in Yet. Ak. Handl, 

 1823, p. 115. 



Has at first sight a considerable resemblance to Lecanora poriniformis 

 Nyl. The verrucae sometimes occur 2-3 together, and the ostioles are 

 occasionally tinged pale-reddish. Rarely 1-5 apothecia are seen in 

 each verruca. 



Sab. On old stems of Ericas in alpine and subalpine localities. — Distr. 

 Sparingly on the N. Grampians and iu the X. Highlands of Scotland. — 

 B. M. : Morrone, Braemar, Aberdeenshire ; near Lairg, Sutherlandshire. 



