BRITISH LICHENS

LECIDEA LECIDEACElE . 21
bluish then wine-red witli iodine.-S. F. Gray Nat. Arr. i. 475;
Hook. Fl. Scot. il. 40 & In Sm. Engl. Fl. v. 185; Mudd Man.
193; Cromb. Lich. Brit. 65; Leight. Lich. Fl. 258; ed. 3, 254.
Lichen lucidus Ach. Pro dr. 39 (1798); Engl. Bot. t. 1550.
EXSlCC. Johns. n. 331; Larb. Crnsar. n. 36; Lich. Rb. n. 306;
Leight. n. 385.
Easily recognized among the allied species by the colour of tho
thallus and of the apothecia. When sterile, as is very frequently tho
case in this country, the thallus has a superfiCIal resemblance to that
of Goniocybe furfuracea, for which it might be mistaken. The bright
colour is due to the presence of rhizocarpic acid III the thallus. When
ligmcolous it is var. thewtea Ach. in Vet. Ak. Hand!. 1808, 270;
Cromb. in Grevillea i. 172; Leight. Lich. Fl. ed. 3, 255; and when
terricolous and herbicolous it is var. jI satura Ach. (fide Th. Fries Lich.
Scand. 432 (1874). These, however, are mere states, both of which
seem to be very rare in Great Britain. The apothecia are usually
somewhat scattered. Frequently the host of Galicium arenanum.
Hab. On shady rocks and walls, seldom on decaying trunks of
trees and grasses on the ground, in lowland and upland situations.­
Distr. General and not uncommon in England, rare in Scotland and
the Channel Islands; not seen fertile in Ireland (fide Carroll).-B. M.
Rozel, Jetsey; Guernsey; Ightham, Kent; Dawlish and near Chagford,
Devon; Trellick, Monmouthshire; Knigh tsford Bridge, W orcestershire;
Llanderfel, near Bala, Cader Idris and Barmouth, Merioneth;
Oswestry, Shropshire; Ayton Moor, Cleveland, Yorkshire; near
Staveley, Kendal, Westmorland; Keswick, Cumberland; New Galloway.
Kirkcudbright; Glen Creran, Argyll; Craigforth, near Stirling; Falls
of Tummel and Glen Fender, Blair Athole, Perthshire; Killarney,
Kerry.
19. L. clavulifera Nyl. in Flora Iii. 294 (1869) & lxiv. 539
(1881).-Thallus effuse, thin, granulate or subleprose, the granules
often somewhat scattered, white, greyish-green or yellowishgreen
(K -, CaCI-). Apothecia minute, convex, immarginate,
sordid-ochraceous or testaceous-red, blackish or black; paraphyses
coherent; epithecium and hypothecium pale; spores
oblong or clavate, very minute, 4-6 fL long, 1 fL thick; hymenial
gelatine bluish then tawny-wine-red with iodine.-Cromb. in
Grevillea vi. 115; Leight. Lich. Fl. ed. 3, 255.
A variable plant as to the colour of the thallus and apothecia;
it is, however, well characterized by the minute, clavate spores. '1'he
gonidia are small and minutely clustered. In Lapland, where it was
originally gathered, it is corticolous. In our saxicolous specimens the
thallus IS very thin and more or less scattered. The apothecia are
numerous and constantly convex.
llab. On shady rocks and stones of walls in an upland situation.
-B. ]}f. Near CIifden, Connemara, Galway.
Form subviridicans Nyl. in Flora Ix. 463 (1877).-ThalluB
greenish. Apothecia and spores as in the species.-Cromb. in
Grevillea vi. 115; Leight. Lich. Fl. ed. 3, 255 (errore suOviridans).
Exsicc. Larb. Lich. Hb. n. 29.