366 LicnEjfACEi. [LECANOKA. 



20. L. Lallavei Nyl. ex Stiz. St. Gall. Nat. Ges. 1880, p. 347. 

 Thallus determinate, tbickish, smooth, rimoso-areolate, subeffigu- 

 rate at the circumference, chalky-white (K ). Apothecia small, 

 subinnate, at first lecanorine with thin thalline margin, at length 

 biatorine and immarginate, bright-rusty- or blood-red (K + dark 

 crimson) ; spores ellipsoideo-oblong, polari-bilocular, 0,008-12 mm. 

 long, 0,004-7 mm. thick. Crorab. Lich. Brit. p. 46 ; Leight. Lich. 

 Fl. p. 223, ed. 3, p. 212 (pro parte). Callopisma Lallavei Mudd, 

 Man. p. 139, t. ii. f. 44. Lecidea Lallavei Clem. Ess. (1807) 

 p. 295. 



Allied to the preceding species, but differs in the more tartareous, milk- 

 white thallus, and the at first lecanorine apothecia. The thallus is 

 sometimes described as limited by a thin, dark hypothallus, but this 

 apparently belongs to a plant with which, at times, it grows associated. 

 The apothecia are numerous and often crowded. 



Hab. On calcareous rocks and walls in maritime districts. Distr. Seen 

 only very sparingly from S. and S.W. England and S.E. Ireland 

 B. M. : Isle of Wight, Hampshire; St. Austell, Cornwall. Lower Glan- 

 nrire Road, co. Cork. 



Subgen. 5. LEPROPLACA Nyl. Flora, 1883, p. 107. Thallns 

 leprose, soft, vitelline, sublobate. Apothecia and spermogoues un- 

 known. 



Entirely leprarioid, having much the same relation to Placotlinm as 

 Leproloma to A-inphiloma. 



21. L. xantholyta Nyl. Flora, 1879, p. 361. Thallus subleprose, 

 thin, crenulato-subeffigurate at the circumference, golden-citrine- 

 coloured (K+ purplish), internally white. Cromb. Grevillea, viii. 

 p. 112, xviii. p. 45. 



While in some respects allied to L. cirrochroa, with which it occasionally 

 grows associattd (as also with L. callopisma), it at once differs in being 

 internally white. The thallus spreads extensively over the substratum 

 and is always sterile. 



Hab. On shady calcareous rocks in maritime and upland districts. 

 Distr. Local, though plentiful where it occurs, in S.W., Central, and 

 N. England, N. Whales, and the Central Highlands of .Scotland. B. M. : 

 Swanage, Dorsetshire ; Anstey's Cove, Torquay, Devonshire ; Bath- 

 anipton Downs, Gloucestershire ; Buxton, Derbyshire ; View Edge, 

 near Stokesay, Shropshire; Great Orme's Head, Carnarvonshire ; Scout 

 Scar, Westmoreland. Craig Tulloch, Blair Athole, Perthshire. 



Subgen. 6. CANDELARIA (Mass.), Nyl. Flora, 1881, p. 454 

 (cfr. Cromb. Grevillea, xviii. p. 45). Thallus subeffigurate or en- 

 tirely granulose, yellow or vitelline. Apothecia lecanorine ; spores 

 8nae or numerous (12-16-32nae), ellipsoid, simple or apically 

 bilocular, rarely 1-septate ; hymenial gelatine not tinged, but the 

 apices of the thecae bluish with iodine. Spermogoncs with long 

 simple sterigmata and straight spermatia. 



