BACIDIA | LECIDEACE® 477 
Hab. On fallen leaves of Salix repens on sand-dunes.— Distr. Rare 
in W. England (Ainsdale, Lancashire). 
21. B. muscorum Mudd. (Part 2, p. 159.) 
Var. atriseda Wheld. & Trav. tom. cit. p. 129.—Thallus 
effuse, granulose, the granules bright-green when moist, cinereous 
when dry, scattered over a black hypothallus. Apothecia solitary 
or aggregate, at first pale-tawny, becoming black, with a thin 
margin soon disappearing, at length convex and difform ; epithe- 
cium blackish ; hymenium brownish ; hypothecium reddish-brown ; 
spores straight or slightly curved, acute at one, or both poles 
sometimes with an appendage, 30-39 pu long, 2—3 yp thick. 
Forming patches which appear blackish owing to the black hypo- 
thallus, it differs from the species in colour and habitat. (The 
appendages suggest germination of the spores.) 
Hab. On decaying mosses and thin moist humus on bare low Salix 
repens dunes associated with Cladonia pyxidata. 
BUELLIA De Not. (Part 2, p. 165.) 
Page 168. Under B. biloculata A. L. Sm. add :—synonym 
Lecanora biloculata Nyl. in Flora Ixi. p. 248 (1878); Cromb. 
Monogr, i. p. 383. 
RHIZOCARPON Ramond. (Part 2, p. 187.) 
3a. Rh. lotum Stizenb. ex Bausch Flecht. Baden, p. 152 
(1869).—Thallus effuse, thin, pulverulent, pale ochraceous or 
cinereous-grey. Apothecia minute, scattered or congregate, black, 
with a persistent margin; hypothecium reddish-brown ; para- 
physes coherent, the epithecium blackish-brown ; spores halonate, 
sparsely rauriform, colourless then pale-brown, 18-22 yp long, 
8-10 p» thick.—B. de Lesd. in Bull. Soc. Bot. Fr. li. p. 517 
(1906) ; Lillie in Scott. Bot. Rev. p. 153 (1912). 
Near to Rh. alboatrwm (Part 2, p. 188). 
Hab.—On granitic rocks. Collected by D. Lillie at Houstry, Dun- 
beath, Caithness. 
Orper XX. DIRINACEZS. (Part 2, p. 200.) 
Thallus crustaceous, attached by hyph, corticate on the 
upper surface, the cortex of closely packed upright hyphal 
branches disposed at right angles to the surface (fastigiate). 
Algal cells Trentepohlia. Apothecia discoid or somewhat elon- 
gate, with proper and thalline margins ; hypothecium and disc 
dark-coloured ; spores elongate, septate. Spermogones with 
simple sterigmata and acicular bent acrogenous spermatia. 
