72 LECANO-LECIDEEI [lECIDKA 



Scarcely to be distinguished outwardly from L. crustidata, but 

 differing in the lighter coloured hypothecium, the somewhat smaller 

 spores, and the colour reaction of the thallus. 



Hah. On chalk and flints. — Distr. Not common in S. and central 

 England.— -B. M. Shanklin, I. of Wight ; Matlock, Derbyshire. 



120. L. polyantha Tayl. ex Leight. Lich. Fl. ed. 3, p. 252 

 (1879). — Thallus pale-brown, tartareous, thin, plane, rimulose- 

 areolate, furfuraceous (K -f yellow, CaCl + orange-yellow). Apo- 

 thecia black, small, innate, sessile, with a thick prominent 

 entire margin ; hypothecium pale-reddish ; paraphyses distinct, 

 pale at the tips, spores ellipsoid or oblong, 0,011-12 mm. long, 

 0,007 mm. thick ; hymenial gelatine blue, the asci brown, with 

 iodine. Specimen not seen. 



Hah. On sandstone. — Distr. Eare in S. England and Wales. 



121. L. confluens Ach. Meth. p. 40 (1803) pro parte.— 

 Thallus determinate or subefTuse, thickish, faintly cracked- 

 areolate, opaque, smoky -white or bluish-grey (K — , CaCl — , 

 medulla I 4- violet) ; hypothallus black. Apothecia moderate in 

 size or somewhat large, scattered or crowded and often confluent, 

 appressed or adnate, plane and marginate, becoming convex and 

 immarginate, black ; hypothecium brownish-black ; paraphyses 

 slender, greenish or dark-olive-brown at the apices ; spores 

 ellipsoid, rather small, 0,009-15 mm. long, 0,005-7 mm. thick : 

 hymenial gelatine deep blue with iodine. — S. F. Gray Nat. Arr. 

 i. p. 464 pro parte; Hook, in Sm. Engl. Fl. p. 175; Tayl. in 

 Mackay Fl. Hib. ii. p. 118 pro parte ; Cromb. Lich. Brit. p. 80 

 (excl. var.) ; Leight. Lich. Fl. p. 295 ; ed. 3, pp. 303-4 (inch 

 forms Isevigata and rimoso-areolata). L. contigua var. y confluens 

 Mudd Man. p. 210 (1861). Lichen confluens Weber Spicil. Fl. 

 Goett. p. 180, t. 2 (1778) ; With. Arr. ed. 3, iv. p. 8 (excl. vars.) ; 

 Engl. Bot. t. 1964. 



ExsicG. Cromb. n. 182; Mudd. n. 180; Johns, nos. 383, 384. 



Differs from L. contigua in the frequently confluent apothecia, 

 the chemical reaction of the medulla, and the much smaller spores. 

 Where the apothecia are complicate by excessive lateral pressure and 

 reticulate from the prominent margins it is f. complicata Leight. 

 (Lich. Fl. ed. 3, p. 304), represented in the British Museum by two 

 specimens from Cader Idris, Merioneth, and from Morrone, Braemar, 

 Aberdeenshire. In f. steriza Leight. (l. c.) the thallus is evanescent ; 

 in f. minor Leight. (?. c.) the apothecia are minute, plane or convex, 

 and more or less confluent. 



Hah. On rocks and stone walls. — Distr. Common in mountainous 

 districts, rare in S. England. — B. M. Near St. Austell, Cornv/all ; 

 Ardingly Kecks and Arundel, Sussex ; Ulting, Essex ; Ayton Moor, 

 Cleveland, Yorkshire ; Cader Idris, Merioneth ; Snowdon, Carnarvon- 

 shire ; West Water, Fife ; Sidlaw Hills, Forfarshire ; Ben More, 

 Ben Lawers, Cairn Gowar, Blair Athole and near Killin, Perthshire ; 

 Achosragan Hill, Appin, Argyll ; Ben Nevis, Invernessshire ; Morrone, 

 Braemar, Aberdeenshire. 



