518 LICHEXACEI. [URCEOLAKIA. 



Blaeberry Hill, and Craig Tulloch, Perthshire ; Morrone and Craig Guie, 

 Braemar, Aberdeenshire. Deer Park, Belfast, co. Antrim ; near Kilcully, 

 co. Cork ; Killarney, co. Kerry ; Glen Inagh, Connemara, co. Galway. 



2. U. gypsacea Ach. Lich. Univ. (1810) p. 338. Thallus thick, 

 soft, continuous, rugoso-unequal, pulverulent, white (K , CaCl ^ 

 red, I~). Apothecia moderate, black, caesio-pruinose ; the thalline 

 margin tumid, inflexed, the proper margin subrugose ; spores 

 (rarely 2na3) 5-septate, muriform, ellipsoid, 0,033-57 mm. long, 

 0,016-24 mm. thick. Cromb. Grevillea, xix. p. 60. U. scruposa 

 forma gypsacea Leight. Lich. Fl. p. 234, ed. 3, p. 239. Urceolaria 

 scruposa f3. albissima Ach. Meth. (1803) p. 147 (nomen informe). 



Usually considered as only a variety of L. urceolata differing in the 

 softer, white, pulverulent thallus, this has now been rightly separated 

 by Nylander on account of the negative reaction on the medulla with 

 iodine (vide Norrl. Fl. Karel. Oneg. p. 27). We have thus another 

 instance of the judgment of older authors being confirmed by modern 

 chemical tests. In the British specimens the apothecia are more or less 

 scattered. 



Hab. On calcareous and cretaceous rocks in maritime and upland 

 tracts. Distr. Only a very few localities in S. and Central England, 

 S. Wales, and W. Ireland; probably often overlooked. B. M. : The 

 Downs, Lewes, Sussex ; Bathamptou Downs, Somersetshire ; N. Derby- 

 shire. Aberdw Rocks, Brecknockshire. Glencorbot, co. Galway. 



3. U. actinostoma Pers. ex Ach. Lich. Univ. (1810) p. 288. 

 Thallus subdeterminate, thickish, smooth, rimoso-areolate, the 

 areolae more or less convex, greyish white (K , CaCl-f-red, I7y ue )- 

 Apothecia minute, immersed, one or several in each areola, sub- 

 globose, at length explanate, blackish, caesio-pruinose, the proper 

 margin finely plicato-striate ; the thalline margin thick, entire or 

 slightly crenulate ; paraphyses very slender, intricate ; spores Snae, 

 ovoid or ellipsoid, 5-0-septate, muriform, 0,030-34 mm. long, 

 0,016-20 mm. thick. Cromb. Journ. Bot. 1885, p. 196. 



A singular species with much the aspect of a Verrucaria, in which 

 genus it was placed by Acharius (/. c.). In the essential characters, 

 however, of the fructification it is clearly an Urceolaria, the apothecia, 

 though long remaining as if verrucarioid, having the disk ultimately open, 

 plane and margined as in the other species of the genus. The British 

 specimens are scarcely typical, but belong rather to the following variety. 



Var. /3. csesioplumbea Nyl. Flora, 1873, p. 70. Thallus some- 

 what shining, greyish leaden-coloured ; otherwise as in the type. 

 Cromb. Grevillea, xix. p. 60. 



Differs in the characters given, though perhaps only as a well-marked 

 form depending on the habitat. 



Hab. On rocks in maritime districts. Distr. Only very sparingly 

 in the Channel Islands and N.W. England. B. M. : Chateau Point, 

 Island of Sark. St. Bees, Cumberland. 



