LECANORA, | LECAN 0-LECIDEEI, 351 
Characterized by the type of the thallus, which is comparable with 
that of Parmeliopsis, and by the structure of the spermogones, which are 
immersed, their ostioles being concolorous with the thallus. 
S77 
(\ 
Fig. 59. 
Lecanora (Squamaria) crassa Ach.—a. A theca and paraphysis, x 350. 
b. Two spores, X500. c. Sterigmata and spermatia, x 500. 
2. L. eragsa Ach. Lich. Univ. (1810) p. 413.—Thallus indeter- 
minate or suborbicular, subcartilaginous, loosely adpressed, thick, 
squamoso-imbricate, pale-livid or pale-yellowish ; squamules some- 
what depressed, roundly lobato-crenate (K—). Apothecia mode- 
rate, sessile, plane or somewhat convex, reddish-brown, the thalline 
margin entire, at length excluded ; spores ellipsoid or oblongo-ellip- 
soid, 0,011-14 mm. long, 0,005-6 mm. thick—Cromb. Grevillea, 
xviii. p. 44; Hook. Fl. Scot. ii. p. 51.—Squamaria crassa Sm. Eng. 
Fl. v. p. 193; Mudd, Man. p. 127; Cromb. Lich. Brit. p. 44; 
Leight. Lich. Fl. p.171, ed. 3,p.157. Psoroma erassum Gray, Nat. 
Arr. i. p. 444. Lichen crassus Huds. Fl. Ang]. ed. 2(1778), p. 530 ; 
Eng. Bot. t. 1893. Lichen cartilagineus Lightf. Fl. Scot. ii. p. 815 ; 
With. Arr. iv. p. 29. Lichenoides cartilagineum, scutellis fulvis 
planis Dill. Muse. 179, t. 24. f.74.— Brit, Exs.: Leight. n.5 ; Larb. 
Cesar. n. 73; Lich. Hb. n. 333; Cromb. n. 157; Bohl. n. 2; 
Dicks. Hort. Sic. n. 24. 
The largest British species of the subgenus, with the thallus usually 
very much expanded, rarely smaller and somewhat orbicular, often here 
and there whitish. With us it is much less variable than it is in warmer 
regions, presenting only the following form. It is usually well fertile, the 
apothecia becoming rather large in age. 
Hab. On the ground and on rocks, chiefly calcareous, in maritime and 
upland districts. Distr. General and common in England and Wales; 
rarer in Scotland, Ireland, and the Channel Islands.—B.M.: Quenvais, 
Island of Jersey; Islands of Herm and Guernsey. Hurstpierpoint, 
Sussex; Berry Head, 8. Devon; St. Merryn, Cornwall; Cleeve Hull and 
Cheddar Cliffs, Somersetshire ; St. Vincent’s Rocks, Bristol, Gloucester- 
shire; Pont Eynon, Glamorganshire ; near Tenby, Pembrokeshire ; Aber- 
dovey, Merionethshire ; Snowdon and Great Orme’s Head, Carnarvon- 
