i
m
III
S.AA'. Highlands of Scotland and N.AA'. Ireland.—B. JI. ; Glen Creran,
Barcaldine, Argyleshire. Letterfrack, Connemara, co. Galway.
97. L. præpostera A'yl. Flora, 1873, p. 19.—Thallus deter-
ininato, th in , smoothish, areolato-rimose, whitish, d arkly limited and
Biibflmbriate a t the circumference (K + yellow, then cinnabarine-
reddish, CaCl — ). Apotheoia moderate, blackish, opaque, glaucous-
suffused or siibdenudate, the tlialliue margin rugulose or suborenate ;
spores ellipsoid, 0,009-14 mm. long, 0,005-6 mm. thiok ; paraphyses
slender ; epitheoium yollow-inspersed ; h}'menial gelatine, especially
tho theoæ, bluish with iodiue.—Cromb. Grevillea, 1873, p. 141 ;
Leight. Lioh. Fl. ed. 3, p. 173.
Looks at first sight as if only a peculiar variety of X. atrynea, hut is
well distinguished by the smaller spores, the reactions of the thallus and
hymenial gelatine. The two specimens seen by me are evidently an old
state of the plant, and tliough tho apothecia are numerous the spores are
seldom present.
Ilab. On basaltic rocks in a maritime district —Distr. Extremely
local and rare in one of tlie Channel Islands.—B. M. ; Rozel, Island of
Jersey.
98. L. albella Ach. A'et. Ak. Ilan d l. 1810, p. 137 ; Nyl. Flora,
1872, p. 365.— Thallus determinate, th in , smooth, whitish (K +
yellow, CaCl — ). Apothecia moderate, plane or slightl}’ convex, pale-
flesh-coloured, oæsio-pruinose or naked, th e th allin e margin entire ;
paraphyses not very discrete ; epithecium granulose (CaCl — ) ; spores
0,010-12 mm. long, 0,005-8 mm. th io k ; hymenial gelatine bluish,
th en nearly colourless or somewhat j'ellowish, the theoæ tawny
wine-red (th eir apices bluish) w ith iodine.—Gray, Nat. A rr. i.
p. 453 ; Sra. Eng. Fl. v. p. 191 ; Mudd, Man. p. 148 ; Cromh. Lioh.
Brit. p. 51 ; Leight. Lioh. Fl. ed. 3, p. 206.—X. subfusca forma
albella Leight. Lioh. F l. ed. i. p. 204. Lichen albellus Pers. in Ust.
Ann. Bot. xi. (1794) p. 18 ; Eng. Bot. t. ?154.
In several respects allied to more than one of the preceding species, from
wliich externally it may be discriminated by the pale huff-coloured apothecia,
which are rather scattered or sometimes crowded. I t is, however,
more definitely separated by the spermogones, which, as stated by Nylander
(Flora, 1872, p. 250, note 2), are pale above. The spermatia are
0,016-20 mm. long (fide Nyl. in litt.). I t is a somewhat variable plant,
pre.senting the following forms.
Hab. On smooth bark of trees in wooded maritime and upland districts.
—Distr. As yet only here and there sparingly in Great Britain and Ireland.—
B. M. : Epping Forest, Essex; New Forest, H an ts; Falls of
Becky, S. Devon ; Savernake Forest, AViltshire ; Hay Park, Herefordshire
; Island of Anglesea. Barcaldine, Argyleshire ; Morrone, Braemar,
Aberdeenshire. Killaloe, co. Clare.
Form 1. peralbella Nyl. ex Cromb. Jo u rn . Bot. 1876, p. 361.—
Thallus as in th e type. Apothecia small, pale-brownish, slightly
pruinose ; hymenial gelatine bluish, th en wine-red w ith iodine.—
ri
- m
419
Lecanora peralbella Nyl. Flora, 1872, p. 365 ; Leight. Lich. Fl. ed 3
p . 206.
_ Originally regarded by Nylander as specifically distinct, this is now
viewed by him only as a form characterized by the reaction of the
hymenial gelatine.
Hab. On thorns and trunks of trees in a maritime district—Distr. A'ery
rare in N.AV. Irelaud.—B. M. : Killery Bay and Ballyiiahinch, Connemara,
CO. Galway.
Form 2. subalbella Nyl. ex Hué, Rev. Bot. 1887, p. 161.—■
Spores 0 ,0 0 9 -1 1 mm. long, 0 ,0 0 5 -7 mm. thick ; hymenial gelatine
and th e thecæ bluish, th en d arker with iodine.—Cromb. Grevillea,
xviii. p. 68.— Lecanora subalbella Nyl. Flora, 1872, p. 365.—Lichen
rosellus Eng. Bot. t. 1651 (apotheoiis magis convexis).
Only another form of X. albella, though more distinct than the preceding,
differing not merely in the reaction of the hymenial gelatine but
also in the slightly smaller spores and the slightly longer spermatia, wliich
Jide Nylander are 0,016-22 mm. long.
Hab. O i l the trunks of trees in wooded maritime and upland tracts.—■
Distr. Only sparingly in S. England.—B. M. ; N etle}' Abbey, near Bartly
Lodge, and Bramble Hill, New Forest, Hants.
99. L. angulosa Ach. Lioh. Univ. (1810) p. 364 ; Nyl. Flora,
1872, p. 250.—Thallus d eterminate, thin, smooth, at length unequal
or rugoso-subrimose, greyish-white (K + yeUow, CaCl — ). Apotheoia
small or submoderate, plane or slightly convex, crowded and
subangulose, pale-brown or sordid-pale, slightly cæsio-pruinose
(epitheoium CaCl + yellow) ; th e th a llin e margin th in , subentire or
somewhat orenulate, a t length subevanescent ; paraphyses slender,
subdiscrete ; epitheoium granulose ; spores 0 ,0 0 9 -1 6 mm. long,
0 ,0 0 6 -9 mm. th ic k ; hymenial gelatine p ersistently bluish with
iodiue.—Leight. Lich. Fl. ed. 3, p. 205.'—X. albella subsp. angulosa
Cromb. Lioh. Brit. p. 51 ; var. fl. angulosa Mudd, Man. p. 148.
X. subfusca var. angulosa Leight. Lioh. Fl. ed. 1, p. 204. Lichen
angulosus Sohreb. Spioil. (1771) p. 136.—B r it. E xs. : Mudd, nos.
114, 115.
Usually regarded as only a variety (or subspecies) of X. albella, this
essentially ditiers in the positive reaction of the epithecium with CaCl,
and in the black colour of the spermogones above. Among minor characters
it also differs in the crowded angulose apothecia, especially in the
centre of the thallus, aud in the rather larger spores. The spermatia are
shorter than in the preceding species, being (fide Nyl. in litt.) 0,014-18
mm. long.
Hab. On trunks of trees, rarely on old pales, in maritime and upland
districts.—Distr. Here and there in Great Britain and Ireland ; not seen
from the Channel Islands.—B. M. ; Epping Forest, Essex; near Lewes
and Hastings, Sussex; New Forest, Hants; Ullacombe, Bovey Tracey,
S. Devon ; Cirencester, Gloucestershire ; Cliffrigg and near Easby, Cleveland,
Yorkshire ; Catterleen, Cumberland. Appin, Argyleshire ; Finlarig,
2 e 2