LEC.-VXORA.] 



LECANO-LBCIDEKI. 



3'37 



Subsimilar in the colour of the thallus and apotheeia to subgenus 

 Plat-odium, but differs, among minor marks of distinction, in the absence 

 of chrysophanic acid, and more essentially in the charaster of the sterig- 

 mata. 



1 



i) 

 O 



Fig. 02. 



(1) Lecanora (Cnndelaria) laciniosa Nyl. a. A iheca and paraphysis, X 350. 

 b. Three spores, X 500. c. Sterigmata and spermatia, X 500. (2) Lecanora 

 medians Nyl. d. A theca and paraphysis, X 350. e. Three spores, X 500. 



. Thecae polyspored. 



22. L. crenata Xyl. Not. Sallsk. pro F. et Fl. F. Forh. v. (1886) 

 p. 130. Thallus orbicular, closely adnate, crenato-granulose, 

 narrowly radiato-effigurate at the circumference, citrine-yellow, 

 opaque; radii convex, crenato-incised (K ). Apotheeia moderate, 

 somewhat plane, pale-citrine or livid-yellow (K ), the thalline 

 margin crenate ; spores 20-40nae (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. 160, 

 ed. 3, p. 166. The specific name crenulata AVahlenb. Fl. Lapp, 

 p. 416, has priority, but cannot be retained, because of the previous 

 homonym of Dickson. 



Looks like a Placodium, but the ahsence of any reaction, the number 

 of the spores, aud ihe nature of the sterigmata place it in this subgenus. 

 In the t\vo British specimens seen, the thallus is not very well developed, 

 and only one is sparingly fertile. 



Hnb. On rocks in maritime districts. Distr. Very local and rare in 

 X. AVales and N.E. Scotland. B. M. : Aberdovey, Merionethshire. 

 Portlethen, Kincardineshire. 



23. L. laciniosa Xyl. Flora, 1881, p. 451. Thallus suborbicular 

 or effuse, minutely laciniato-divided, greenish-yellow ; laciniae mul- 

 tifid, subimbricate, crowded, the margins crisp, more or less granu- 

 loso-pulvcrulent (K ). Apotheeia small, subsessile, tawny-yellow 

 (K ), the thalline margin entire or granulate; spores (10-100na3) 

 ellipsoid, simple, often subpolari-bilocular, variable in size, 0,006- 

 0,01 1 mm. long, 0,004-6 mm. thick. Cromb. Grevillea, xviii. p. 45. 



