LECANORA.] LECANO-LECIDEEI. 307 
Subsimilar in the colour of the thallus and apothecia to subgenus 
Placodium, but differs, among minor marks of distinction, in the absence 
of chrysophanic acid, and more essentially in the character of the sterig- 
mata, 
lo 
Fig. 62. 
(1) Lecanora (Candelaria) laciniosa Nyl.—a. A theca and paraphysis, x 350. 
bd. Three spores, X 500. ¢. Sterigmata and spermatia, x 500. (2) Lecanora 
medians Nyl.—d, A theca and paraphysis, x 350. e. Three spores, x 500. 
a. Thece polyspored. 
22. L. crenata Nyl. Not. Sillsk. pro F. et Fl. F. Férh. v. (1886) 
p. 180.—Thallus orbicular, closely adnate, crenato-granulose, 
narrowly radiato-effigurate at the circumference, citrine-yellow, 
opaque; radii convex, crenato-incised (K—). Apothecia moderate, 
somewhat plane, pale-citrine or livid-yellow (K—), the thalline 
margin crenate; spores 20-40nz (or more), ellipsoid or oblong, 
simple or obsoletely L-septate, 0,009-0,015 mm. long, 0,004-7 mm. 
thick.—Cromb. Grevillea, xviii. p. 45; Leight. Lich. Fl. p. 180, 
ed. 3, p. 166. The specific name crenulata Wahlenb. Fl. Lapp. 
p. 416, has priority, but cannot be retained, because of the previous 
homonym of Dickson. 
Looks like a Placodium, but the absence of any reaction, the number 
of the spores, and the nature of the sterizmata place it in this subgenus. 
In the two British specimens seen, the thallus is not very well developed, 
and only one is sparingly fertile. 
Hab. On rocks in maritime districts —Distr. Very local and rare in 
N. Wales and N.E. Scotland—B. M.: Aberdovey, Merionethshire. 
Portlethen, Kincardineshire. 
23. L. laciniosa Nyl. Flora, 1881, p. 454.—Thallus suborbicular 
or effuse, minutely laciniatu-divided, greenish-yellow ; laciniee mul- 
tifid, subimbricate, crowded, the margins crisp, more or less granu- 
Joso-pulverulent (K—). Apothecia small, subsessile, tawny-yellow 
(K—), the thalline margin entire or granulate; spores (10-100nz) 
ellipsoid, simple, often subpolari-bilocular, variable in size, 0,006- 
0,014 mm. long, 0,004-6 mm. thick.—Cromb. Grevillea, xviii. p. 45. 
