PHISC1A.] PHYSCIEI. 307 



L'niv. (1810) p. 474. Lichenoides glaucum orbiculare, segmentis 

 Jatiusculis, scutellis nigris Dill. Muse. 177, t. 24. f. 71 B. 



The milk-white pruina with which the thallus and apothecia are 

 covered is often but little dense. It has somewhat the appearance of 

 subsp. pityrea, from which it at once differs in the absence of soredia. 

 The apothecia are rare in the British specimens. 



Hab. On trunks of trees in maritime and mountainous districts. 

 Distr. Very local and scarce in S. England, the Central Grampians, 

 Scotland, and S.W. Ireland. B. M. : Isle of Wight. Craig Tulloch, 

 Blair Athole, Perthshire. Adare, co. Limerick. 



Var. /3. subvenusta Nyl. Bull. Soc. Linn. Normand. ser. 2, t. vi. 

 (1872) p. 285. Thallus more or less pruinose. Apothecia mode- 

 rate or somewhat large, pruinose, the receptacle crowned at the 

 base. Physcia pulvendenta f. laciniolata Cromb. Journ. Bot. 1872, 

 p. 358. P. pulverulenta var. venusta Leight. Lich. Fl. p. 147 pro 

 parte, ed. 3, p. 136 pro parte. Lichen pulverulentus Eng. Bot. 

 t. 2063. Lichen stellaris ft. Lightf. Fl. Scot. ii. p. 824 ; y. Huds. Fl. 

 Angl. ed. 2, p. 534 ; var. 3, With. Arr. ed. 3, iv. p. 31. Lichenoides 

 scutellis limbo cinereo crispo cinctis Dill, in Ray Syn. ed. 3, p. 75. 



Distinguished by the lacinioli or lobules which crown the base of the 

 receptacle, in which respect it is subsimilar to subsp. venusta. Occa- 

 sionally the thallus also is more or less covered with minute suberect 

 lobules. The apothecia are generally numerous, and, in entire specimens, 

 some have the receptacle nearly or quite naked. 



Hab. On the trunks of old trees in maritime and upland districts. 

 Distr. Somewhat local and scarce in England ; rare in S. Scotland and 

 among the S. Grampians. B. M. : Norwich, Norfolk ; Henfield and 

 Glynde, Sussex ; Respringand near Penzance, Cornwall ; Kemble, Wilt- 

 shire ; Windsor Great Park, Berkshire ; near Cambridge ; Oswestry, 

 Shropshire ; Levens, Westmoreland. Ravelrig, near Edinburgh ; Fin- 

 larig, Killin, Perthshire. 



Var. y. angnstata Nyl. Act. Soc. Linn. Bord. ser. 3, i. (1856) 

 p. 308. Thallus somewhat small, pale greyish-red or subcervine, 

 cpruinose ; laciniae narrow, discrete, beneath densely blackish-hispid 

 with rhi/iniae. Apothecia rather small, naked or pruinose, brown 

 or brownish-black. Cromb. Lich. Brit. p. 38 ; Leight. Lich. Fl. 

 p. 147, ed. 3, p. 135. Borrera pulverulenta /3. angustata Mudd, 

 Man. p. 110. Lichen angustatus Hoffm. Enum. (1784) p. 77, t. 11. 



The narrow discrete laciniae and the numerous rhizinas render this a 

 well-marked variety. In its typical condition, as noticed by Acharius, 

 Lich. Univ. p. 474, the laciniaB are continuous from the centre to the cir- 

 cumference ; but intermediate states occur in which the Iacinia3 are shorter 

 and not so continuous, as is usually the case in Britain. The apothecia 

 in our specimens are not very numerous. 



Ilab, On the trunks of old trees in upland districts. Dittr. Local and 



x2 



