THLTCTIS.] LECAXO-L'ECIDEEI. 513 



brook, Isle of Wight; New Forest, Hants; Ilsham Walk, Torquay, 

 S. Devon ; Bathampton Downs, Somersetshire ; Cirencester, Gloucester- 

 shire ; Harboro' Magna, Warwickshire ; Huglith, near Church Stretton, 

 and Oswestry, Shropshire : Barmouth and Aberdovey. Merionethshire ; 

 Airyholme Wood and Hoggart's W T ood, Cleveland,* Yorkshire. Kits- 

 boro', Riverstone and Castlebernard Park, co, Cork ; Dunkerron, 

 Killarney, co. Kerry. 



2. P. argena Koerb. Syst. Lich. Germ. (1855) p. 391. Thallus 

 effuse, thin, smootbish or rugose, pulverulent, silvery-grey or 

 cream-coloured (K + yellow, then deep red). Apothecia minute, 

 brownish-black, csesio-suffused ; spores solitary, oblong or cylindrico- 

 oblong, very large, 0,100-0,140 mm. long, 0,027-50 mm. thick. 

 Mudd, Man. p. 280 ; Cromb. Lich. Brit. p. 61 ; Leight. Lich. Fl. 

 p. 246, ed. 3, p. 237. Variolaria argena Turn. & Borr. Lich. 

 Brit. p. 75; Sm. Eng. Fl. v. p. 171. Lichen aryenus Ach. Prodr. 

 (1798) p. 8 ; Eng. Bot. t. 1923. 



Subsimilar to the preceding, from which it at once differs in the non- 

 apiculate spores. It usually cccurs only in a sterile condition, when it 

 is \ fry apt to be overlooked. The apothecia are either scattered or 

 aggregate, and in the former case are with difficulty detected by the 

 naked eye. 



Hob. On the trunks of old trees in upland tracts. Distr. Local (at 

 least in fruit) in S. and W. England. B. M. : Epping Forest, Essex ; 

 Ightham, Kent; New Forest, Hants; Haslemere, Surrey ; Beckey Falls 1 , 

 S. Devon ; Burnham Beeches, Bucks ; Charnwood Forest, Leicester- 

 shire ; Barmouth, Merionethshire ; Oswestry, Shropshire. 



65. THELOTREMA Ach. Meth. (1803) p. ISOproparte; Nyl. 

 Mem. Soc. Cherb. t. iii. (1855) p. 324. Thallus thinly crustaceous, 

 continuous, containing chrysogonidia. Apothecia verrucaeform, at 

 first closed, then open, with a proper and a thalline margin ; spores 

 variable in number (l-4nse or 8nse), oblong or fusiform, usually 

 colourless ; paraphyses slender ; hymenial gelatine not tinged with 

 iodine. Spermogones with simple sterigmata and short straight 

 spermatia. 



A germs well characterized by the fructification. Nearly all the 

 species are exotic and natives of warm regions. The three which occur 

 in Europe, one of which is confined to our Islands, belong to the sub- 

 genus Euthelotrema Nyl. 



1. T. lepadhram Ach. Meth. (1803) p. 132 pro paite ; Syn. 

 p. 115. Thallus subeffuse or rarely determinate, thin, smooth or 

 slightly ruguloso-un equal, protuberant around the apothecia, whitish 

 or cream-coloured (K -f- red , CaCl ) Apothecia submod erate, urceo- 

 lato-scutelliform, dark-brown or blackish, caesio-pruinose or naked ; 

 the proper margin lacerate, inflexed, the thalline margin thin, even ; 

 spores (4nse) 8nae, oblongo -fusiform, colourless, 0,035-70 mm. 

 long, 0,011-16 mm. thick. Leight. Angio. Lich. p. 31, t. 12. f. 1; 

 Lich. Fl. p. 247, ed. 3, p. 238 ; Cromb. Lich. Brit. p. 61 ; Mudd, 

 Man. p. 278, t. 5. f. 116 ; Turn. & Borr. Lich. Brit. p. 180 ; Sm. 

 Eng. Fl. v. p. 161 ; Gray, Nat. Arr. i. p. 494 ; Hook. Fl. Scot. ii. 



2L 



