356 



LICHENACEI. 



[LECAXOIU. 



Allied to subgenus Squamaria, under -which the species have usually 

 been included, but distinguished by the cephalodia, which are constant in 

 all the species (most of which are exotic) under all conditions of growth. 



a 



8. L. gelida Ach. Lich. Univ. 

 (1810) p. 428. Thallus orbicular, 

 closely adnate, rimoso-arcolate in 

 the centre, laciniato-radiose at the 

 circumference, sordid-white or pale- 

 greyish (K+ yellow, CaCl -f- red) ; 

 cephalodia scattered, greyish- or 

 brownish-flesh-coloured. Apothe- 

 cia moderate, adnate, concave or 

 plane, pale-testaceous, the thalline 

 margin thick, entire ; spores ellip- 

 soid, 0,014-18 mm. long, 0,006-8 

 mm. thick. Cromb. Journ. Linn. 

 Soc. Bot. xv. p. 232; Hook. PL 

 Scot. ii. p. 50 ; Tayl. in Mack. PL 

 Hib. ii. p. 140. Squamaria gelida 

 Sm. Eug. PL v. p. 195; Mudd, 

 Man. p. 129; Cromb. Lich. Brit, 

 p. 45 ; Leight, Lich. PL p. 174, ed. 3, 

 p. 159. Placodium gelidum Gray, 

 Nat. Arr. i. p. 448. Lichen gelidus 

 Linn. Mant. ii. (1771) p. ]33; 



Dicks. Crypt, fasc. ii. p. 19 ; With. Arr. iv. p. 26 ; Eng. Bot. t. 699. 

 Brit. Exs. : Dicks. Sort. Sic. n. 25 ; Larb. Lich. Hb. u. 50. 



Fig. 00. 



Lecanora (Placopsis) gelida Ach. a. 

 A gonimic glomerule and gonimic 

 granules, X 350. b. Two spores, 

 X 500. c. Sterigmata and sper- 

 matia, X 500. 



Easily recognized amongst British Lecanorei by the cephalodiiferous 

 thallus, which is usually of moderate size, greyish-flesh-coloured when 

 moist, and occasionally sprinkled with greyish or greyish-olive, impressed 

 soredia. The cephalodia, which are more or less numerous according to 

 the development of the thallus, are depresso-verrucarioid, at length radi- 

 ato-rimose, internally with the gonimia glomerulose, or often several moni- 

 liform. The apothecia, when present (for the thallus is often sterile), are 

 usually sparingly scattered. A young sterile state, with the thallus little 

 developed and scattered and bearing a few young cephalodia, is form dis- 

 persa (non Fr.), Cromb. Grevillea, i. p. 171 ; Leight. Lich. Fl. iii. p. 160. 



Hob. On rocks, granitic, schistose, and old red sandstone, in upland and 

 subalpine districts. Distr. Rather local in England and Wales, more 

 frequent in Scotland, and probably also in Ireland. B. M. : St. Austell, 

 Cornwall ; Cader Idris, Dolgelly, and Llyn Bodlyn, Merionethshire ; 

 Eglestone and Teesdale, Durham ; near Kendal, Westmoreland ; Knock 

 Morton Screes, Cumberland. New Galloway, Kirkcudbrightshire ; Loch 

 Awe, Argyleshire; Craig Calliach, Ben Lawers, and Craig Tulloch, 

 Perthshire ; Clova and Canlochan, Forfarshire ; Glen Caudlic and Glen 

 Cluny, Braemar, Aberdeenshire ; Rothiemurchus, Ben Nevis, and Fort 

 Augustus, Inverness-shire ; Hills of Applecross, Ross-shire. Dunkerron, 

 and Connor Cliffs, Dingle, co. Kerry ; Letterfrack and Recess, Conne- 

 rnara, co. Galway ; Carnlough, co. Antrim. 



