352 UCHENACEI. [LECANORA. 



shire ; Rhyl, Flintshire ; Beaumaris and Puffin Island, Anglesea ; Llan- 

 gollen, Denbighshire ; Dovedale, Derbyshire ; Oswestrv, Shropshire ; 

 Eglestone, Durham ; Whitbarrow, Westmoreland. Arthur's Seat, Edin- 

 burgh ; Black Isle and Island of Lismore, Appin, Argyleshire. Morning- 

 ton, co. Meath ; KilJarney, co. Kerry. 



Form melaloma Ach. Lich. Univ. (1810) p. 414. Thallus with 

 the squamules rounded and subentire, here and there blackish at the 

 margins. Cromb. Grevillea, xviii. p. 44. Brit. Exs. : Mudd, n. 91. 



Differs in the squamules being less crenate and more or less blackish at 

 the margins. It is often, however, confluent with the type, from which it 

 is scarcely to be distinguished unless as a state. 



Hob. On calcareous rocks in upland situations. Distr. Apparently 

 only in W. and Central England. B. M. : Near Buxton, Derbyshire'; 

 Durdham Downs, near Bristol, Gloucestershire. 



3. L. lentigera Ach. Lich. Univ. (1810) p. 423. Thallus orbi- 

 cular, crustaceo-foliaceous, moderate, loosely appressed, areolato- 

 squamose in the centre, radiato-lobed at the circumference, whitish 

 or pale-whitish, subpruinose ; lobes plane or somewhat concave, un- 

 dulato-crenate (K ). Apothecia adnate, pale- testaceous, the thai- 

 line margin thin, entire ; spores ellipsoid or oblong, 0,009-12 mm. 

 long, 0,045-0,005 mm. thick. Cromb. Grevillea, xii. p. 61. Squa- 

 maria lentigera Sm. Eng. Fl. v. p. 195 ; Mudd, Man. p. 128, t. ii. 

 f. 40 ; Cromb. Lich. Brit. p. 44 ; Leight. Lich. Fl. p. 172, ed. 3, 

 p. 159. Placodium lentigerumGreiy, Nat. Arr. i. p. 447. Lichen lenti- 

 gerus Weber, Spicil. (1778) p. 192 ; Dicks. Crypt, fasc. i. p. 11 ; Eng. 

 Bot. t. 871 ; With. Arr. iv. p. 27. 



Closely allied to L. crassa,into which, as observed by Nylander (Lich. 

 Scand. p. 131), it seems to pass in the South of France. It is, however, 

 distinguished by the thallus being smaller (at least twice as small), thin- 

 ner, and differently coloured ; while it is also effigurato-radiating at the 

 circumference. The apothecia are numerous, submoderate, at length sub- 

 biatorine, with the thalline margin excluded. 



Hob. On cretaceous soil in maritime and upland tracts. Distr. Found 

 only sparingly in S. and E. Central England ; now almost extinct. B. M. : 

 Isle of Wight, Hampshire ; Newhaven, Sussex ; Gpgmagog Hills and New- 

 market Heath, Cambridgeshire. 



4. L. chrysoleuca Ach. Lich. Univ. (1810) p. 411. Thallus 

 lobato-squamose, peltate-affixed, ochroleucous or whitish-straw- 

 coloured ; beneath sordid-pale, broadly blackish towards the circum- 

 ference ; squamules firm, imbricate, lobed, plane, crenate or crenato- 

 incised at the circumference (K ). Apothecia moderate, generally 

 crowded, concave or plane, reddish-flesh-coloured, the thalline margin 

 thin, flexuose ; spores ellipsoid, 0,009-12 mm. long, 0,0045-65 mm. 

 thick. Cromb. Grevillea, xviii. p. 44. Squamaria chrysoleuca 

 Leight. Lich. Fl. ed. 3, p. 158. Lichen chnisolencus Sm. Trans. 

 Linn. Soc. i. (1791) p. 82, t. 4. f. 5. 



