LECANORA.] 



LECANO-LECIDEEI. 



349 



A large genus comprising several subgenera, formerly ranking as 

 distinct genera, but not sufficiently diftoring to warrant this arrangement. 

 Indeed, so intimately are they related that Nylander seems at times in- 

 clined to regard them as only leading sections. Some of these with bia- 

 toroid apothecia have sometimes been arranged under the Lecideei; but 

 in most cases tlie apothecia are, at least in a young state, lecanorine, with 

 the margin containing gonidia. In other instances the character of the 

 spermogones indicates their true relati<jn. 



Subgenus 1. PSOROMA Xjl. Not. 8allsk. pro F. et PI. F. Forh. 

 V. (1880) p. 125. — Thallus scjuamulose or subgranulose, internally 

 cellular. Apothecia lecanorine ; spores 8nyc, ellipsoid, simple ; 

 hymenial gelatine bluish, then wine-red with iodine. Spermogones 

 with jointed sterigmata and short cylindrical spermatia slightly 

 thickened at either apes. — Psoroma Ach. Prodr. (17'J8) p. 91 pro 

 minima parte ; Kyi. Mem. Soc. Cherb. iii. (1885) p. 322. 



At once distinguished by the entirely cellular structure of the thallus. 

 Most of the species are exotic, and of the few which are European, only 

 one occurs in this countrv. 



ooQOOOOco'gOoS', 







^^MiiUm^S^. 



Fig. 58. 



Lecanora (Psoroma) hypnorum Ach. — a. Vertical section of thallus, x200. 

 b. Spores, X 500. c. Sterigmata and spermatia, X 500. 



1. L. hypnorum A.ch. Syn. (1814) p. 193 ; Xyl. K^t. SaUsk. pro 

 F. et Fl. F. Forh. v. (1866) p. 125. — ThaUus indeterminate, squa- 

 muloso-granulate, yeUowish-brown or tawny-yellow ; squamules 

 minute, crenate or granulate (K — ). Apothecia moderate or some- 

 what large, at first urceolate, then plane, red or brownish, the thai- 

 line margin granuloso-crenate ; spores often somewhat acute at 

 either apex, 0,016-21 mm. long, 0,008-11 mm. thick; hymenial 

 gelatine bluish, then wine-red with iodine. — Cromh. Grevillea, xii. 

 p. 60 ; Hook. Fl. Scot. ii. p. 51 ; Tayl. in Mack. Fl. Hib. ii. p. 139. 



