LECANORA..] LECANO-LECIDEEI. 469 



The colour of the thallus, as in other similar instances, depends upon 

 the presence of peroxide of iron in the substratum. In the British speci- 

 mens the apothecia are numerous and at times angulose from mutual 

 pressure. Only a few spermogones are visible, with spermatia 0,004-5 

 mm. long, about 0,001 mm. thick. 



Hab. On moist mica-schist rocks in an alpine situation. Distr. Only 

 on one of the S. Grampians, Scotland. B. M. : Above Loch-na-Gat, 

 Ben Lawers, Perthshire. 



167. L. recedens Nyl. Flora, 1879, p. 361. -Thallus determinate, 

 thick, subverrucoso-unequal, rimoso-diffract, greyish (K , CaCl , 

 medulla I ). Apothecia small, innate, brownish-black, colourless 

 within ; the thalline margin slightly prominent ; spores 8nse, sub- 

 globose or ellipsoid, 0,009-14 mm. long, 0,007-9 mm. thick ; para- 

 physes thick, jointed ; epithecium brownish ; hymenial gelatine 

 slightly bluish, then wine-red with iodine. Cromb. Grevillea, xix. 

 p. 57.Lecidea recedens Tayl. in Mack. Fl. Hib. ii. (1836) p. 117. 

 Lecanora subcinerea Nyl. Flora 1869, p. 82 ; Cromb. Journ. Bot. 

 1875, p. 140 ; Leight. Lich. Fl. ed. 3, p. 197. Brit. Exs. : Larb. 

 Lich. Hb. n. 299 (macrior). 



Well distinguished from the allied species by the subglobose spores 

 and the articulate paraphyses. It approaches L. cinereorufescens, but 

 from this it differs also in the thicker thallus, the negative reaction of the 

 medulla with iodine, and the shorter spores. Our British specimens are 

 for the most part well fertile. Though describing it as a Lecidea, Taylor 

 /. c. says that it is allied to Urceolaria cinerea. 



Hal). On rocks in maritime and mountainous districts. Distr. Only in 

 N. Wales, N. England, and W. Ireland. B. M. : Llyn Bodlyn, Bar- 

 mouth, Merioneth ; Holwick Scar, Yorkshire. Dunkerron, co. Kerry ; 

 Derryclare, Connemara, co. Galway. 



168. L. pelobotrya Somm. Lapp. Suppl. (1826) p. 99 ; Nyl. Lich. 

 Scand. p. 155. Thallus determinate, tartareous, thickish, areolato- 

 verrucose, the verrucae gibbose or somewhat plane, smooth, crowded, 

 whitish (K ,CaCl ). Apothecia moderate, plane, slightly im- 

 mersed in the areolae, brownish-black ; the thalline margin rather 

 thick, inflexed ; spores 4-8nae, ellipsoid or oblongo-ellipsoid, 

 0,023-35 mm. long, 0,012-16 mm. thick; hypothecium brownish- 

 black or blackish ; paraphyses slender ; hymenial gelatine bluish 

 with iodine. Leight. Lich. Fl. ed. 3, p. 195. Aspicilla pdobotrya, 

 Mudd, Man. p. 164. Letidea pelobotrya Cromb. Lich. Brit. p. 80 ; 

 Leight. Lich. Fl. ed. ] , p. 298. Urceolaria pelobotryon Wahl. in 

 Ach. Meth. Suppl. (1803) p. 31. 



A rather peculiar species of this section, which from the dark hypo- 

 thecium might be taken for "ALecidea. The distinct thalline margin, how- 

 ever, of the apothecia in well-developed specimens shows that it is a true 

 Lecanora. The thallus, which has a whitish evanescent hypothallus, is 

 at first plane and continuous, becoming at length thickish and verrucose, 



