LECANORA. ] LECANO-LECIDEEI. 349 
_A large genus comprising several subgenera, formerly ranking as 
distinct genera, but not sufficiently differing 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 Lecideed; but 
in most cases the 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 relation. 
Subgenus 1. PSOROMA Nyl. Not. Sallsk. pro F. et Fl. F. Forh. 
v. (1886) p. 125.—Thallus squamulose or subgranulose, internally 
cellular. Apothecia lecanorine; spores 8n:e, ellipsoid, simple ; 
hymenial gelatine bluish, then wine-red with iodine. Spermogones 
with jointed sterigmata and short cylindrical spermatia slightly 
thickened at either apex.—Psoroma Ach. Prodr. (1798) p. 91 pro 
minima parte ; Nyl. Mém. 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 couutry. 
lb, 
cosa 
o008 
RoR 
0 
09°90 
Gyo, 
Ae) 
a 
=a 
(aXe) 
2 
Bo 
go 
0.099022, 00 
900 ,05,00 
Sitateeeel sak ea 
Fig. 58. 
Lecanora (Psoroma) hypnorum Ach.—a. Vertical section of thallus, x 200. 
5. Spores, x 500. vc. Sterigmata and spermatia, x 500. 
1. L. hypnorum Ach. Syn. (1814) p. 193; Nyl. Not. Sillsk. pro 
F. et Fl. F. Forh. v. (1866) p. 125.—Thallus indeterminate, squa- 
muloso-granulate, yellowish-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 thal- 
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.—Cromb. Grevillea, xii. 
p. 60; Hook. Fl. Scot. ii. p. 51; Tayl. in Mack. Fl. Hib. ii. p. 189. 
