350 LICHENACEI. [LECANORA. 



Psoroma Tiypnorum Hoffm. Deutsch. Fl. ii. (1795) p. 166 ; Cromb. 

 Lich. Brit. p. 44 ; Leight. Lich. Fl. p. 163, ed. 3, p. 149 ; Gray, Nat. 

 Arr. i. p. 445. Pannaria Tiypnorum Mudd, Man. p. 124. Squa- 

 maria Tiypnorum Sm. Eng. Fl. v. p. 194. Lichen Tiypnorum Dicks. 

 Crypt, fasc; iii. p. 14 ; With. Arr. iv. p. 22 ; Eng. Bot. t. 740. 

 Brit. Exs. : Larb. Caesar, n. 70 ; Cromb. n. 58 pro parte. 



Internally somewhat resembling more developed states of Pannaria 

 brunnea, with which it is confounded in some of our older herbaria, but 

 is definitely separated by the texture of the thallus. The plant is more 

 or less effuse, with the squamules either somewhat discrete, or imbri- 

 cately crowded, or sometimes little developed according to the habitat. 

 The hypothallus is very rarely visible, and only in corticolous speci- 

 mens, where it is thin, greyish or greyish-brown (vide Nyl. Pyr. Or. 

 p. 125). The apothecia are generally numerous, becoming larger in old 

 plants. 



Hob. Among mosses on the ground, rocks, and walls in maritime and 

 upland districts. Distr. Rather local in England, N. Wales, and the 

 Channel Islands, more frequent in Scotland ; not recorded from Ireland. 

 B. M. : Grosnez, Island of Jersey ; Island of Guernsey. Yarmouth, 

 Suffolk ; Respring, Cornwall ; Tresco, Scilly Islands ; Kale's End, near 

 Malvern, Worcestershire ; Aberdovey, Merionethshire ; Eglestone, Dur- 

 ham ; The Cheviots, Northumberland. Pentland Hills, near Edinburgh ; 

 Hills above Greenock, Renfrewshire ; Barcaldine, Argyleshire ; Killin, 

 Craig Calliach, Ben Lawers, and Glen Fender, Perthshire ; Clova and near 

 Dundee, Forf arshire ; Craig Cluny, Braemar, Aberdeenshire ; Glen Nevis, 

 Inverness-shire. 



Form deaurata Nyl. Not. Sallsk. pro F. et Fl. F. Forh. v. (1866) 

 p. 125. Thallus bright-yellow or tawny-yellow. Apothecia rather 

 large, with concolorous thalline margin. Cromb. Grevillea, xviii. 

 p. 44. Psoroma Tiypnorum form deaurata Nyl. Lich. Scand. p. 121 ; 

 Cromb. Lich. Brit. p. 44. Lecanora lepidora ft. deaurata Ach. Lich. 

 Univ. (1810) p. 418. Brit. Exs. : Cromb. n. 58 pro parte. 



Differs merely in the more yellowish thallus and the normally larger 

 apothecia. When the thallus is less developed it is more luxuriant at the 

 margins of the apothecia. 



Hob. Among mosses on boulders and walls in maritime and upland 

 districts. Distr. Seen only from N. Wales and the Highlands of Scot- 

 land. B. M. : Cwm Bychan, Merionethshire. Appin, Argyleshire ; Glen 

 Lochay, Killin, Perthshire ; Corriemulzie, Braemar, Aberdeenshire. 



Subgenus 2. SQUAMABJA Nyl. Not. Sallsk. pro F. et Fl. F. 

 Forh. v. (1866) p. 125. Thallus radiately laciniate or cartila- 

 gineo-squamose. Apothecia lecanorine ; spores 8nso, ellipsoid, 

 simple, colourless ; hymenial gelatine bluish with iodine. Sper- 

 mogones with simple sterigmata and long, arcuate, spermatia. 

 Squamaria DC. Fl. Fr. ii. (1805) p. 374 ; Nyl. Mem. Soc. Cherb. iii. 

 p. 177. 



