LECIDEA] LECIDEACEZ 469 
23. L. coarctata Nyl. (Part 2, p. 22.) 
Instead of thallus CaCl+deep-red insert :—-CaCl — or + red- 
dish ; and after spores ellipsoid add :—when young often tinged 
with pale rose-colour and with large oil globules, 14—26 pw long, 
7-12 p» thick. 
L. humigena Tay]. in Lond. Journ. Bot. vi. p. 150 (1847).— 
Substratum of the thallus cuticular, gelatinous, whitish with 
scattered minute roundish brown verruce ; gemme (gonidia ?) 
granular, crowded, minute, oblong, subangular. Apothecia 
greenish, hemispherical, subpellucid, pale-brown, immarginate,. 
the dise seabrid. 
Probably near to or synonymous with DL. vernalis (Part 2, p. 33).. 
though Taylor says it can scarcely be confounded with that species. 
Hab. On wet clay banks; Dunkerron, Kerry. 
L. filamentosa Stirt. 1. c—Thallus whitish or pallid, rugulose,. 
sometimes dispersed-areolate. Apothecia small (*2—‘4 mm. wide), 
brownish-black, plane, acutely marginate, becoming convex and. 
scarcely marginate ; hypothecium colourless ; paraphyses slender, 
irregular, not well discrete, with sordid-brownish apices ; spores. 
8 in the ascus, colourless, simple, oblong or oblong-ellipsoid, 11— 
16 » long, 5-6 » thick; hymenial gelatine blue then yellow with 
iodine. 
Might be allied to L. albohyalina Nyl. in Sect. Biatora (Part 2, 
p. 39). 
Hab. On fallen or worked wood near Killin, Perthshire. 
1124. L. petrosa Arn. in Flora li. p. 36 (1868).—Thallus 
thinly crustaceous, whitish or bluish-white, sometimes finely 
cracked-areolate or almost obsolete. Apothecia sessile or adnate, 
solitary or two or three together, at first plane, with a prominent 
margin, brownish-black ; hypothecium black; paraphyses stoutish, 
conglutinate, the hymenium faintly blue-green or ceerulescent, 
the epithecium dark, purplish-, bluish- or greenish-brown ; spores. 
ellipsoid, large, 16-30 » long, 9-13 » thick; hymenial gelatine 
blue with iodine. 
Distinguished by the ceruleous blue colour in the hymenium and 
by the large spores. A variety albo-suffusa (L. eyaniza Nyl. in 
Flora lv. p. 359 (1872) ) has been recorded by Th. Fries (Lich. Scand. 
p. 512) with pruinose apothecia. 
We are indebted for the discovery and determination of this 
interesting species to Mr. T. Hebden. 
Hab. On calcareous rocks.—B. M. Malham, Yorkshire. 
L. mersata Stirt. 1. c—Thallus pallid or pallid-glaucous, 
sometimes reddish-ferruginous, thin, almost continuous, smooth, 
here and there rimulose-areolate (K—, CaCl—). Apothecia 
