402 CYCLOCARPINEE [ UMBILICARIA 
Easily known by the pustules, the development of which is due to 
unequal intercalary growth. The thallus is greenish when moist. 
Apothecia are rather rare in British specimens. It is chiefly a 
mountainous or northern lichen. 
” 
Hab. On rocks and boulders, rarely on old walls, in maritime or 
upland regions.— Distr. Not uncommon in rocky districts throughout 
the British Isles.—B. M. La Moye and New Gorey, Jersey; Guernsey; 
Helminton, Cornwall; Blackstone Rock, near Bovey Tracey, Hay 
Tor and Hunter Tor, Dartmoor, and near the Teign, Devon; Malvern 
Hills, Worcestershire ; Charnwood Forest, Leicestershire; Nesscliffe 
Hill and Caer Caradoc, Shropshire; Cwm Bychan, Merioneth; Capel 
Curig and Nant Gwynant, Carnarvonshire; Nepha, Westmoreland ; 
Wastdale, Cumberland; New Galloway, Kirkcudbrightshire; Loch 
Corruisk, Skye; Ben Nevis, Invernessshire; Sandy Loch, near 
Lerwick, Shetland; Mizzen Head and Glengariff, Cork; near 
Dunkerron, Kerry. 
Orper XVII. CLADONIACEA. 
Thallus usually of twofold character: primary thallus 
crustaceous or squamulose, often evanescent, corticate or non- 
corticate, attached to the substratum by the hypothallus, by 
rhizine or occasionally by a branching rhizoid ; secondary thallus 
or podetium upright, varying from a short apothecial stalk to a 
simple or branched usually tubular structure, corticate or non- 
corticate, tapering to a point or opening out into a trumpet- 
shaped scyphus. Algal cells Protococcus. Apothecia sessile on 
the tips of the podetia or on the margin of the scyphus, rarely 
on the primary thallus, immarginate ; paraphyses generally 
unbranched ; spores simple or variously septate, colourless. 
Spermogones closely associated with or replacing the apothecia, 
with branching sterigmata and acrogenous spermatia. 
* 
The upright thallus, though mostly endogenous in origin, and 
regarded sometimes as an apothecial stalk, has become by meta- 
morphosis an organ of absorption and assimilation and functions as 
a vegetative thallus. 
The following British genera are included in the family :— 
Podetia short, usually simple. 
Podetia glabrous. 
Thallus granular, spores 2—4-septate............ Beomyces. 
Thallus a gelatinized crust, spores up to 
LOO-BSPHATC, «0. 6.5600 cad ccnstiesensos emacs Gomphillus. 
Podetia granular. 
Thallus granular, spores simple ................. Pilophorus. 
Podetia usually well developed. 
Podetia with a solid stalk, minutely squamulose, 
spores 4-pluriseptate..............stdsssnseveeneni Stereocaulon. 
Podetia with a hollow stalk, spores simple......... Cladonia. 
