PHYSCIA.] PHY8CIET. 313 



Form exempta Fr. fil. Lich. Scand. (1871) p. 140. Laciniae 

 shorter, broader, imbricate, naked or very sparingly and shortly 

 ciliate : otherwise as above. Parmelia tenella var. exempta Tayl. in 

 Mack. Fl. Hib. ii. p. 147. Borrera tenella y. exemta Ach. Lich. 

 Univ. (1810) p. 499. As noticed by Taylor, I. c., his specimen was 

 referred by Borrer to P. erosa. 



Seems to be merely a modification of the type, from which it is distin- 

 guished, at least as a well-marked form, by the characters of the lacinite. 

 Our only British specimen is sterile. 



Hob. On the trunks of willows in upland situations. Distr. Seen only 

 sparingly from S.W. Ireland. B. M. : Ballynegarde, co. Limerick. 



14. P. aipolia Nyl. Flora, 1870, p. 38. Thallus orbicular, stel- 

 lari-appressed, multifido-laciniate, whitish ; beneath concolorous with 

 greyish-browii rhizinae ; lacinioe somewhat plane, narrow, subcon- 

 tiguous. discrete, and with the apices crennlate at the circumference 

 (K^Tyellow, CaCl~). Apothecia submoderate, somewhat convex, 

 brownish-black, csesio-pruinose or naked, the thalline margin entire ; 

 spores 0,016-26 mm. long, 0,008-11 mm. thick. Cromb. Journ. 

 Bot. 1870, p. 97. Lichen aipolius Ach. Prodr. (1798) p. 112. 

 Physcia stelldris var. acrita Cromb. Lich. Brit. p. 39. P. aipolia, 

 form acrita Cromb. Journ. Linn. Soc. Bot. xvii. p. 571. Lichen 

 stellaris Huds. Fl. Angl. p. 448 (ex specimine in Herb. Huds.). 

 Lichenoides cinereiim, segmentis angustis stellatis, scutellis niyris 

 Dill. Muse. 176, t. 23. f. 70, A, B. 



Frequently not distinguished, even as a variety, from the preceding, to 

 which it is subsiiuilar. The planer, more divided lactni;e, which are 

 discrete at the circumference, and especially the positive reaction of the 

 medulla, well characterize it and raise it to its Acharian specific rank. 

 In its typical condition (a. acrita Ach. Lich. Univ. p. 477) the thallus is 

 entirely smooth in a young state, but at length becomes slightly rugose 

 in the centre. It is usually well fertile, the apothecia being chiefly 

 central. 



Hob. On the trunks and branches of trees in cultivated tracts, often in 

 orchards, rarely on old pales, very rarely on calcareous walls, of maritime, 

 lowland, and upland districts. Distr. Rather local in S. and N. England, 

 N. Wales, the S.W., Central, and N. Highlands of Scotland, and in N.W. 

 Ireland. B. M. : Near Lewes, Sussex ; Shanlilin, Isle of Wight ; Ilaham 

 Valley, Torquay, S. Devon ; Penzance, Cornwall ; Hafod, Cardiganshire ; 

 Dolgelly, Merionethshire ; near Kendal, Westmoreland. Appin, Argyle- 

 shire : Killin and foot of Ben Lawers, Perthshire ; Castleton of Braemar, 

 Aberdeenshire ; Applecross, Koss-shire. Kylemore and Lough Inagh, 

 Connemara, co. Galway. 



Var. /5. anthelina Cromb. Grevillea, xv. (1887) p. 78. Thallus 

 narrowly laciniate, beneath with black rhi/iua3 ; laciniaj more dis- 

 crete, somewhat convex. Apothecia submoderate, crowded or scat- 

 tered, at length slightly convex, the thalliue margin entire. 



