RHIZOCARPON] LECIDEACEiE 197 



escent (K+ pale-yellow, CaCl — ); hypothallus black, often obso- 

 lete. Apothecia black, varying in size, plane, innate-sessile or 

 adnate with an obtuse, thick margin, which rarely almost dis- 

 appears ; hypothecium brownish - black ; paraphyses slender, 

 coherent, dark-brown towards the apices ; spores oblong-ellipsoid, 

 colourless, becoming brownish, muriform, halonate, 0,024-50 mm. 

 long, 0,012-18 mm. thick ; hymenial gelatine deep-blue with iodine. 

 — Bh. petraeum var. lavatum Mudd Man. p. 220 (1861). Lecidea 

 petrsea var. obscurata Ach. Lich. Univ. p. 156 (1810); f. lavata 

 Cromb. Lich. Brit. p. 86 (1870). L. obscurata Schier. Spicil. 

 p. 130 (1828); Leight. Lich. Fl. ed. 3, p. 377. L. atroalha 

 var. concreta Wahlenb. Fl. Lapp. p. 471 (1812). L. concreia 

 Leight. Lich. Fl. p. 351 (1871). L. lavata Nyl. in Flora Ivi. 

 p. 23 (1873); Cromb. in Journ. Bot. xi. p. 135 (1873); Leight. 

 Lich. Fl. ed. 3, p. 378. 



The thallus is occasionally shining and almost copper-brown or 

 sometimes tinged a rusty-red (f. ferrata Nyl. Lich. Scand. p. 234 

 (1861) ). The apothecia vary in size, but are usually rather large, 

 strongly marginate, and occasionally also umbouate. When growing 

 on rocks liable to be submerged, the thallus almost disappears 

 (f. lavata). 



Hah. On rocks. — Distr. Somewhat rare in upland or subalpine 

 regions. — B. M. Pulborough, Sussex ; Llandyssil, Cardiganshire ; 

 Aberdovey, Merioneth ; Nant Francon and Trefriw Falls, Carnarvon- 

 shire '. Caradoc, Shropshire ; near Thirsk, Yorkshire ; Portlethen, 

 Kincardineshire ; Barcaldine, Argyll ; Stirlingshire ; Ben Lawers, 

 Perthshire (f. ferrata) ; Glen Callater, Braemar, Aberdeenshire ; Ben 

 Nevis, Invernessshire ; Applecross, Eossshire ; Killarney, Kerry. 



14. Rh. plicatilis A. L. Sm. — Thallus dirty -white, minutely 

 plicate or warted, cracked-areolate (K-|- yellow, CaCl-f yellow) ; 

 hypothallus brown. Apothecia blackish-brown, large, closely 

 adnate, sometimes connate, the margin obtuse, undulate, becoming 

 attenuate and obliterated in age ; hypothecium thick, Vjlackish- 

 brown paraphyses stoutish, subdiscrete, yellowish-brown at the 

 tips ; spores 4-8 in the ascus, elongate-ellipsoid, muriform, colour- 

 less, becoming faintly brownish, halonate, 0,027-30 mm. long, 

 0,009-10 mm. thick ; hymenial gelatine deep-blue with iodine. — 

 Hh. coniopsoideum Hepp ex Arnold in Flora Ixvii. p. 593 (1884) 

 (fide Arnold). Lecidea plicatilis Leight. in Ann. Mag. Nat. 

 Hist. ser. 4, iv. p. 201 (1869) & Lich. Fl. p. 351 ; ed. 3, p. 380 ; 

 Cromb. in Journ. Bot. viii. p. 98 (1870). L. coniopsoidea Hue 

 in Bull. Soc. Linn. Norm. ser. 4, viii. p. 314 (1894). 



Hue I. c. notes that in some specimens the thallus changes from 

 yellow to red on the application of potash. 



Hab. On alphie rocks. — B. M. Llyn-y-Cae, Cader Idris, Merioneth. 



15. Rh. geminatum Kocrb. Syst. Lich. Germ. p. 259 (1855), 

 emend. Th. Fr. Lich. Scand. p. 623 (1874).— Thallus subeffuse, 

 warted-areolate, the areolce contiguous or somewhat scattered. 



