240 LICHENACEI. [PARMETJA. 



9. P. scortea Ach. Lich. Univ. (1810) p. 461. Thallus orbicular, 

 subcoriaceous, smooth, somewhat shining, very thinly isidiose in the 

 centre, sinuato-lobed, greyish- white or whitish; beneath rugose, 

 brownish, densely black-fibrillose ; lobes short, rounded, undulate, 

 inciso-crenate at the margins (K+y ellowish , CaCl~ redd ; sb ). Apo- 

 thecia moderate, scattered, reddish -brown, the margin subentire ; 

 spores 0,007-1 1 mm. long, 0,005-7 mm. thick. 8m. Eng. Fl. v. 

 p. 203. Parmelia tiliacea var. scortea Mudd, Man. p. 93 ; Cromb. 

 Lich. Brit. p. 33 ; Leight. Lich. Fl. p. 131, ed. 3, p. 122. Lichen 

 scorteus Ach. Prodr. (1798) p. 119 ; Eng. Bot. t. 20(55. Brit. Exs. : 

 Leight. n. 87 ; Larb. Caesar, n. 18. 



Closely allied to P. tiliacea ; but its thicker and less appressed thallus, 

 its normally whiter colour, the central isidia, the form of the lobes, and 

 the more scattered apothecia warrant us in regarding it, with the older 

 authors, as a distinct species, in which light also it is now viewed by 

 Ny lander (Pyr. Or. p. 5). The isidia, which are greyish, becoming 

 blackish in age, though chiefly central, are sometimes sprinkled over the 

 thallus nearly to its circumference. In this country, as elsewhere, the 

 apolhecia are very rare, and even when present are but few. The sper- 

 mogones, which are more common, are similar to those of P. tiliacea. 



Hob. On trees and old pales, rarely on rocks, in maritime and upland 

 districts. Distr. Local arid scarce in England (chiefly in the South), the 

 Channel Islands, and Wales ; very rare in S.W. Scotland and in S. Ire- 

 land. B. M. : L'Etacq, Island of Jersey; Island of Sark. Near Bury 

 St. Edmunds, Suffolk; near Lewes and Hentield, Sussex; Shanklin, 

 Isle of Wight ; New Forest, Hants ; Bolt Head, Devonshire ; Stone- 

 henge, Wilts ; Harboro' Magna and Newbold-on-Avon, Warwickshire ; 

 Twy cross, Leicestershire ; Little Stretton, Shropshire ; Holyland, Pem- 

 brokeshire ; Dolgelly and near Barmouth, Merionethshire; Island of 

 Anglesea ; Stokesley, Cleveland, Yorkshire ; near Eglestone, Durham ; 

 near Stavely, Kendal, Westmoreland. Near Dumfries ; Castle Douglas, 

 Kirkcudbrightshire. Askew Wood and Dunkerron, co. Kerry. 



Form concrescens Cromb. Thallus orbicular, small, isidiose ; 

 lobes very short, narrowly dissected and crowded. Apothecia un- 

 known. 



A panniform condition, referred to in Leight. Lich. Fl. ed. 1, p. 133, as 

 approaching var. concentrica of P. revoluta. It is, however, neither spherical 

 (but only somewhat convex) nor free ; while the isidia and other cha- 

 racters show that it belongs to P. scortea. The specimens seen are 

 sterile. 



Hob. In crevices of stone walls in a maritime district. Distr. Ex- 

 tremely local and rare in S.W. England. B. M. : Bolt Head, S. Devon. 



10. P. saxatilis Ach. Meth. (1803) p. 204. Thallus orbiculari- 

 expanded, membranaceous, subimbricate, reticulato-rugulose, often 

 somewhat isidioso-scabrid, greyish-white or glaucous-grey, beneath 

 black, rhizineo-fibrillose ; lacinite sinuato-incised or sinnato-lobed, 



retuse at the apices ; (Kj^^ blood . recl> Cadi). Apothecia 

 moderate or somewhat large, badious or brownish, the margin thin, 



