LECANORA| LECANORACEE 259 
normally with a prominent thalline margin; spores usually 8, 
rarely many in the ascus, colourless, simple or variously septate. 
Of world-wide distribution. Distinguished from the somewhat 
parallel Order, Lecideacex, by the character of the apothecia, in the 
development of which the thallus takes part, and forms a protective 
margin round the disc. 
Phialopsis (Lecanora rubra Ach.) belongs to Gyalecta, and the 
species of Lecanora sect. Sarcogyne have been placed in Biatorella 
(see Appendix). Psoroma is placed under Pannariacee (p. 89). 
The following British genera are included in the Order :— 
Spores simple. 
Spores 8 or few in the ascus.................,.... 51. Leeanora. 
Spores many in the ascus...........csceeeeseeeee 52. Acarospora- 
Spores septate. 
Spores elongate-ellipsoid, 1-2-septate.......... 53. Lecania. 
Spores elongate-fusiform, 1-3-septate ......... 54. Iemadophilus 
Spores elongate-acicular, pluri-septate ........ 55. Hematomma. 
51. LECANORA Ach. Lich. Univ. p. 77 (1810) pro parte. 
(Pl. 51.) 
Thallus squamulose or variously crustaceous, rarely somewhat 
minutely fruticose, mostly of stratose structure, the cortex of the 
upper surface of decomposed hyphe, or wanting. Algal cells, 
Protococcus. Apothecia generally superficial, sometimes immersed 
at first ; spores usually 8 in the ascus, colourless, simple, mostly 
ellipsoid. Spermogones with acrogenous or rarely pleurogenous 
spermatia. 
In the genus, as here understood, are included the species with 
simple colourless spores, generally 8 in the ascus (up to 382 in 
L. Sambuci). The sections Ochrolechia and Aspictilia are frequently 
regarded as distinct genera, the former on account of differences in 
paraphyses and spores, the latter because of the late development 
of the thalline margin. The species are grouped in the following 
sections :— 
MSE STUDIOS Eich ass:o2 eden ons suee's be vesetencea feenet § i. SQUAMARIA. 
Thallus crustaceous or indistinctly squamulose. 
Apothecia superficial from the first. 
Spores small or moderate in size (less 
faa gin length) ........cedweseceseses § ii, EULECANORA. 
Spores very large, with a thick epispore § iii. OcHROLECHIA. 
Apothecia immersed at first ...........s.eeeeeeeeee § iv. ASPICILIA. 
§ i. Squamaria DC. FI. France. ii. p. 374 (1805) pro parte (as 
the genus Squammaria) ; Hook. in Sm. Engl. Fl. v. p. 192; Mudd 
Man. p. 127; Cromb. Lich. Brit. p. 44; Leight. Lich. Fl. p. 171 ; 
ed. 3, p. 157. Lecanora subg. Squamaria Nyl. in Not. Siillsk. 
Faun. & Fl. Fenn. Forh. v. p. 125 (1866); Cromb. Monogr. i. 
p- 350. Squamaria subg. Placopsis Nyl. in Ann. Sci. Nat. xv. 
p- 376 (1861). Lecanora subg. Placopsis Cromb. Monogr. i- 
p. 355 (1894). 
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