PANNULAKIA.] LECANO-LECIDEEI. 343 



Allied to P. triptophylla, of which it has sometimes been considered as 

 a variety; but it is specifically distinct by the less developed thallus, the 

 typo of the apothecia, and by the spores not being definitely simple. The 

 thallus, which forms a crowdedly diffracto-areolate crust, at times sub- 

 ramuloso-divided, is normally determinate, and is very distinctly limited 

 by a broad, conspicuous hypothallus. Occasionally it is of a dark-brownish 

 colour, as are also the apothecia, whence var. /3 fuscum (Hepp.) Mudd, 

 Man. /. c. The apothecia are numerous, scattered or approximate, 

 sometimes becoming convex with evanescent margin. 



Hab. On calcareous rocks, mortar of walls and flint pebbles, in mari- 

 time, lowland, and upland tracts. Distr. General aud common through- 

 out Great Britain, and no doubt also in Ireland ; rarer in the Channel 

 Islands. B. M. : Gorey, Island of Jersey. Shiere, Surrey; Glynde, 

 Sussex ; Shanklin, Isle of Wight; Anstey's Cove, Torquay, and Paington, 

 S. Devon ; St. Minver, Cornwall ; near Cromford and Buxton, Derby- 

 shire ; near Stroud, Gloucestershire ; Bathampton Down?, Somersetshire ; 

 Llanymynech Hill and Bridgenorth, Shropshire ; Barmouth, Merioneth- 

 shire ; Eglestone. Durham ; Levens, Westmoreland ; near Whitehaven, 

 Cumberland. Appin, Argyleshire ; Ben Lawers and Craig Tulloch, Blair 

 Athole, Perthshire ; Castleton of Braemar, Aberdeenshire ; Applecross, 

 Ross-shire. Near Belfast, co. Antrim. 



Subsp. P. psotina Cromb. Grevillea, xviii. (1889) p. 44. Thallus 

 as in the type. Apothecia internally pale ; spores occasionally 

 3-septate (the septa thin) ; hypothecium almost entirely colourless 

 (or partly pale-brownish). Pannaria nigra subsp. psotina Nyl. ex 

 Cromb. Journ. Bot. 1873, p. 133. P. psotina Leight. Lich. PL ed. 3, 

 p. 156. Pannaria nigra var. psotina Ach.,Jide Nyl. Lich. Scand. 

 (1861) p. 126. Lecothecium nigrum Mudd, Man. p. 175 pro parte, 

 t. iii. f. 65 (middle fig.). Brit. Exs. : Mudd, n. 144. 



Differs in the internal colour of the apothecia and in the spores being 

 rarely triseptate. In our specimens the thallus is subeffuse, with the 

 hypothallus rather narrow and at times little visible. In Flora, 187(3, 

 p. 239, Nylander seems inclined to regard it as a proper species. 



Hab. On mortar of walls and calcareous rocks in maritime and lowland 

 districts. Distr. Only here and there in England and the Channel 

 [slands ; no doubt to be detected elsewhere. B. M. : The Vale, Island 

 of Guernsey. Eastbourne, Sussex ; near the Horse, Windsor Great Park, 

 Berkshire ; Bilsdale, Yorkshire. Hexham, Northumberland ; White- 

 haven, Cumberland. 



5. P. triseptata Nyl. ex Cromb. Grevillea, xviii. (1889) p. 44. 

 Thallus subdeterminate, granuloso-crustaceous, diffracto-areolate, 

 brownish-black; hypothallus blackish, not very distinct. Apo- 

 thecia lecideine, small, thinly margined, black or dark-reddish- 

 brown, internally whitish ; spores ellipsoid, 3-septate, 0,016-23 mm. 

 long, 0,006-9 mm. thick ; hypothecium blackish or brown ; hyme- 

 nial gelatine bluish with iodine. Pannaria nigra var. triseptata 

 Nyl. Lich. Scand. (1861) p. 126 ; Not. Siillsk. pro F. et Fl. F. Forh. 

 v. p. 125 ; Cromb. Lich. Brit. p. 43, subsp. trissptata Nyl. ex Cromb. 

 Grevillea, i. p. 171. 



