PHYSCIA.] PHYSCIEI. 319 



smaller. — IVii/scia ohscnra suhsp. litJiotea Crorab. Grevillea, xv. 

 p. 78 ; form lithotca Leij;lit. Lich. Fl. cd. 8, p. 137. ParnuUa ci/ch- 

 sdis fj. lithotea Ach. Meth. (18U3) p. 1(J9. 



Subsimilar to P. obsmra, but differs in being firmer, more or less furfu- 

 raceous, and e.^pecially in the cellular structure uf the cortex, which 

 consists of rounded cells, being more distinct. In age i.early the whole 

 thallus and the margins of the laciuia3 are covered witli a dark furfur. 

 The state sciuMra (Ach. Meth. Suppl. p. 40) differs merely in being 

 darker and sorediate only at the margins of the lacinise. The apothecia 

 when present (for it is usually sterile) are small and few. 



Hah. In depressions of rocks which are frequently moistened by the 

 sea and by lakes and streams in maritime and mountainous districts. — 

 Distr. Local and scarce in N. England, 2s. Wales (Jide Ix'ight.), auKjng 

 the S. (4rampians, Scotland, and in N.W. Ireland. — B. M. : Near New- 

 ton, Cleveland, Yorkshire ; Teesdale, Durham. Loch Dochart and Ken- 

 more, Perthshire. Counemara, co. Galwaj. 



23. P. olothrix Xyl. Flora, 1875, pp. 360, 442.— Thallus orbicu- 

 lari-stellate, greyish-glaucous or dark-brown, sometimes sublivid, 

 csorediate : beneath black-fibrillose ; laciuife discrete, narrow, linear, 

 multifid, plane, ciliate at the margins, the cilia rigid, horizontal 



(K~, CaCl~). Apothecia moderate, dark-brown, the thalline mar- 

 gin entire, at length inflexed, the receptacle at the base black- 

 fibrillose ; spores oblong, 0,015-25 mm. long, 0,009-12 mm. thick. 

 — Cromb. Liun. 8oe. Journ. Bot. xvii. p. 571. — Physcia ohscura var. 

 vlothriv Cromb. Lich. Erit. p. 39 ; Leight Lich. JFl. p. 149, ed. 3, 

 p. 137. Bon-era ohscura f. xdothrix Mudd, Man. p. 110. Parmelia 

 tdothrix Tayl. in Hack. Fl. Hib. ii. p. 146. Lichen ulothrix Acb. 

 Prodr. (1798) p. 113. Lichen vireUus Eng. Bot. t. 1696 (lower 

 fig.). Lichen ciUatus Dicks. Crypt, fasc. iii. p. 16; With. Arr. 

 ed. 3, iv. p. 30. Lichen stelJaris var. 4, With. I. c. p. 31. Lichni- 

 uicles viride, seqmentis angustis distortis, scidellis jyidlis Dill. Muse. 

 178, t. 24. f. 12^.— Brit. Exs. : Leight. n. 80. 



L'snally regarded by more recent authors as a variety of the preceding ; 

 this was rightly viewed by Achaiius as a distinct species, as warranted 

 more especially by the peculiar character of the marginal cilia and in a 

 minor degi-ee by the radiating hbrillose receptacle of the apothecia. In 

 this latter respect, as already observed, it is analogous to subsp. Parmelia 

 carpvrhizam, though in old phnnts this character is less apparent. When 

 sterile it is readily distinguished by the horizontal marginal cilia of the 

 thallus. The apothecia are numerous and often crowded, and the spermo- 

 gones, which seem to be rather rare, are as in P. obscura. 



Hah. On the trunks of trees, rarely on old pales and walls in maritime 

 and upland districts. — Distr. Occurs only here and there in England, S. 

 Scotland and the Highlands, and S. Ireland. — B. M. : Lakenham and 

 near Yarmouth, Norfolk ; Brighton and Albourne, Sussex : near Pen- 

 zance, Cornwall: Cirencester, Gloucestershire ; Gopsall Park, Leicestei- 

 shire : Buxton. Derby shu-e ; near Worcester. New Gallo-«ay, Kiikcud- 

 brightshire : Appin, Argyleshire ; Finlarig, KiUin, and Glen Fender. Blair 

 Athole, Perthshire. Carrigaloe, near Cork. 



