structure «f tlie spermogones. The thallus, winch is of moderate size, is
often thinly Avhite-pruinose, especially towards the centre, hut becomes
citrine when moistened. The apothecia, which are chiefly central, are iu
age subbiatorine. The spermogones have the spermatia 0,003 mm. long,
0,001 mm. thick.
Hab. On calcareous soil, shell-sand, and in the crevices of rocks in
maritime tracts.—Histr. Local, though not uncoraiuon where it occurs in
the Channel Islands, S. Englaud, and S. VVales.—B. M. : Quenwds,
Island of Jersey : Island of Guernsey. Freshwater Bay, Isle of Wight ;
Newhaven and Rottingdean Cliffs, Sussex ; Bray Ilill, St. Minver,
Cornwall ; Stackpole Court and Lydstep, Peinhrokeshire.
10. L. elegans Ach. Lioh. Univ. (1810) p. 435.—Thallus orbicular,
appressed, stellato-radiate, thickish, orange- or tawny-red ;
laciniæ subdiscrete, multifid, convex, torulose (K - f purplish). Apothecia
moderate, adnate, somewhat concave or nearly plane, concolorous
(K - f purplish), the thalline margin entire ; spores ellipsoid or
ovoid, 0 ,0 1 1 -lG mm. long, 0 ,0 0 0 -9 mm. th ick .—Cromb. Grevillea,
xviii. p. 44 ; Hook. F l. Scot. ii. p. 50 pro pa rte .—Placodium elegans
Mudd, Man. p. 131, t. ii. f. 41 ; Cromb. Lioh. Brit. p. 4 5 ; Leight.
Lich. Fl. p. 178, ed. 3, p. 163. Squamaria elegans Sm. Eug. El.
V. p. 195. Lichen elegans L ink, Ann. Bot. i. (i7 9 4 ) p. 37.—This
is the p lan t of most British authors only in so fa r as relates to the
diagnosis (evidently borrowed from Acharius) given by them, th e
localities aud habitats cited being chiefly erroneous.
A beautiful lichen, somewhat resembling Physcia parietina var. ectanea,
bnt is of an Arctic or Alt-alpine type. From tbe other species of the
subgenus it is easily recognized by the thallus being distinctly corticate
on both sides. Elsewhere in Europe it is ratlier variable, presenting
several well-marked varieties, of which only oue has been met with in
this country. The few' British specimens seen are rarely fertile, the
spermogones also being rare, with spermatia 0,003-4 mm. long, 0,t01
mm. thick.
Hah. On granitic rocks in alpine situations.—Distr. Only very sparingly
among the N. Grampians, Scotland.—B. M. : Lochnagar aud
C.iirngoriu, Braemar, Aberdeenshire.
Var. ft. ten-uis Ach. Sj'n. (1815) p. 183.— Thallus small, thin ;
laciniæ narrow, discrete. Apotheoia small.—Cromh. Journ. Bot.
1885, p. 195.—Lichen elegans ft. tenuis Wahleub. Fl. Lapp. (1812)
p. 417. Lecanora elegans form minor Cromb. Jo u rn . Linn. Soc.
Bot. xvii. p. 571. Placodium elegans ft. cN«c«ia (Schær.), Mudd,
Man. p. 131. Lichenoides tenuissimum, scutellis exiguis minlatis
Hill. Muse. 176, t. 24. f. 68.
Differs in the much smaller thallus, the narrower subfiliform discrete
radii, aud the smaller apothecia. In most British specimens the thallus is
minute, with the ladii somewhat scattered, and very sparingly fertile.
Hab. On calcareous rocks in suhalpine situations.—Distr. Very local
and scarce iu S. VV'ales, N. England, and among the N. Grampians,
Scotland.—B. M. ; Whimhold Bocks, near New Radnor, Radnorshire ;
East Allendale, Nortliiiniherland.- Craig Guie, Braemar, Aberdeenshire.
H . L. m tiro rum Ach. Lich. Univ. (1810) p. 4 4 3 ; Njd. Flora,
1883, p. 106.—Thallus orbicular, closely adnate, usually whitish-
suffused, subrimoso-areolate in the centre, plioato-radiose a t the
oircumferenoo, vitelline-yellow or citrin e; radii somewhat turgid,
crenate and often also iiiciso-plioate at the apices (K -f purplish).
Apotheoia moderate, plane or convex, tawny-yellow, orange-
coloured or concolorous with th e thallus (K -f purplish) ; th e
thalline margin entire, paler or concolorous ; spores 0,0 0 9 -1 5 mm.
long, 0 ,0 0 4 -7 mm. thiok.—Cromb. Grevillea, xviii. p. 4 4 ; Hook.
Fl. Soot. ii. p. 50 pro p a rte ; Tayl. in Mack. F l. Hib. ii. p. 140
pro p a rte .— Placodium murorum Leight. Lioh. Fl. p. 175 pro parte,
ed. 3, p. 161 pro pa rte ; Cromb. Lioh. Brit, p. 45 pro pa rte ; Mudd,
Man. p. 132 pro p a rte ; Gray, Nat. Arr. i. p. 447 pro pa rte . Squamaria
murorum Sm. Eng. El. v. p. 194 pro parte. Lichen murorum
Hoffm. Enum. (1784) p. 63 ; Eng. Bot. t. 2157 (lower fig.). Lichen
Huds. El. Augl. p. 445 pro parte.
I,ii:
, t ■'
A species until recently little understood and very imperfectly limited,
so th a t the trivial name of murorum, as applied to it by British and other
authors, is, to a great extent, a nomen vayum. I t appears under two conditions
of growth—a larger, with the tliallus more developed and extended
(var. ft major Wahl. Fl. Lapp. p. 410) ; and a smaller, with the thallus
rosulate and stunted (var. pulvinata Mass. Symm. Lich. p. 13). Both
states are usually well fertile, the apothecia being numerous and often
crowded. The spermogones liave the spermatia oblongo-hacilliforin,
0,030-35 lum. long, 0,007-0 mm. thick.
Hah. On calcareous rocks and mortar of walls in maritime and lowland
districts.—Disir. No doubt general and common, though seen only from
a few localities iu Great Britain.—B. M. ; Glynde, Sussex ; Anstey s Cove,
Torquay, S. Devon ; St. Austell, Cornwall ; near Cirencester, Gloucestershire
; Great Orme’s Head, Carnarvonshire; Teesdale, Durham : Wark-
worth Castle, Nortliumberland. Morningside, near Edinburgh; Appm,
Argyleshire ; near Aberdeen.
Var. ft. co rtic ico la Nyl. Bull. Soo. Bot. t. xiii. (1866) p. 368.
Thallus smaller, more contracted and less developed, vitelliiie-yellow
or greyish-green. Apothecia numerous, congested; spores (often
subsimple) 0 ,0 1 1 -1 5 mm. long, 0 ,0 0 5 -7 mm. thick.—Cromb.
Grevillea, xviii. p. 44.—B r it. Exs. : Larb. Lioh. Hb. n. 52.
From the structure of the spores prohahly referable rather to the next
subspecies, as suggested hy Dr. Arnold (Flora, 1875, p. 153), though al.-o
approaching suhsp. X. tegularis in e.xternal aspect. The plant, as descnhed
hy Nylander, difiers from the British specimens m the thallus being
greyish-greerij wlieii the reaction with K is less distinct.
Hah. On the trunk of an elm and on old timber in lowland districts.—
Distr. Apparently very rare in S. and E. England.—B. M. : Windsor
Great Park, Berkshire ; Great Willbraham, Cambridgeshire.
Subsp. I . L. decipiens Nyl. Flora, 1869, p. 81 (nota), 1883,
p, 106. Thallus moderate, crowdedly verruoose in the centre, the
verrucæ often eifioresceut with concolorous soredia, peripheral radii
l u