PHYSCIA..] PHY8C1EI. 317 



columnaris Tayl. in Fl. Hib. ii. p. 144, is a more granulose state. 

 Brit. Exs. : Leight. n. 324. 



Easily recognized by the thallus being often almost entirely granulose 

 or leprose, with the laciniai visible only at or towards the circumference. 

 With us it is but seldom and sparingly seen with apothecia. The sper- 

 mogones apparently do not occur in Britain. 



Hub. On the trunks of trees, often in orchards, and on tiled roofs in 

 maritime and lowland districts. Distr. Somewhat local and scarce in 

 S. and Central England, N. Wales, S. Ireland, and the Channel Islands ; 

 not seen from Scotland. B. M. : St. Martin's, Island of Jersey ; Island of 

 Guernsey. Epping Forest, Essex ; near Maidstone and Tunb'ridge Wells, 

 Kent ; near Lewes, between Henfield and Brighton, and Hurstpierpoint, 

 Sussex; near Southampton, Hants ; Ryde, Isle of Wight; near Plymouth, 

 Devonshire ; Penzance, Cornwall ; West Haddon, Northamptonshire ; 

 near Barmouth, Merionethshire. Tervoe, co. Limerick ; Carrigalim, near 

 Cork. 



Form elegans Nyl. ex Leight. Lich. Fl. ed. 3 (1879) p. 139. 

 Thallus glaucous-white ; lacinise finely isidioso-fimbriate at the mar- 

 gins. Apothecia not seen. Brit. Exs. : Larb. Lich. Hb. n. 88. 



The peculiar fimbriate margins of the lacinise, which are not leproso- 

 grauulose, render this a somewhat distinct form. It does not occur 

 fertile. 



Hab. On rocks in a maritime district. Distr. Found only very 

 sparingly in N. W. Ireland. B. M. : Kyleinore Lake, co. Galway. 



20. P. caesia Nyl. Act. Soc. Linn. Bord. ser. 3, i. (1856) p. 308. 

 Thallus orbicular, closely adnate, stellate, multifido-laciniate, 

 ;fesio-white or greyish-white, sprinkled with caesious subglobose 

 ioredia ; beneath pale and sparingly fibrillose ; lacinise narrow, con- 

 vex, contiguous, slightly dilated at the apices (K ^yellow, CaCl~). 

 Apothecia sessile, small, concave or plane, black, naked or pruinose, 

 the thalline margin thickish, entire or crenulate ; spores oblong, 

 0,016-23 mm. long, 0,009-13 mm. thick. Cromb. Lich. Brit. p. 39. 

 Pliyscia stellaris var. ccesia Leight. Lich. Fl. p. 152, ed. 3, p. 141. 

 Borrera ca'sia Mudd, Man. p. 107. Squamaria ccesia Sm. Eng. Fl. 

 v. p. 196. Parmelia ccesia Gray, Nat. Arr. i. p. 443 ; Tayl. in Mack. 

 Fl. Hib. ii. p. 147. Lichen ccesius Hoffm. Enum. (1784) p. 65, 

 t. 12. f. 1 ; Eng. Bot. t. 1052. Lichen Psora Dicks. Ciypt. fasc.iii. 

 p. 17 ; With. Arr. ed. 3, iv. p. 26. Lichenoides cinereum, sey mentis 

 anjutis stdlatis, scutellis nigris Dill. Muse. 176, t. 24. f. 70 c. Brit. 

 Exs. : Leight. n. 323. 



Distinguished from its more immediate allies bv the pulvinate csesious 

 soredia, which are scattered regularly over the thallus and rarely become 

 confluent. The apothecia are chiefly central and not of frequent occur- 

 rence. 



Hab. On walls, roofs, and boulders in lowland and upland districts. 

 Distr. General though not common in England ; much rarer in Scot- 



