minute, somewhat concave, brighte or reddish-testaceous, th e margin
th ick ish ; spores oblong, simple or spuriously 1 -septate, 0 ,0 1 6 -3 0
mm. long, 0 ,0 0 6 -7 mm. thick ; hymenial gelatine ohsoletely bluish,
becoming very faintly wine-red with iodine.—Cromb. Grevillea, iii.
p. 22 ; Leight. Lioh. PL ed. 3, p. 36.
At first sight this might be taken for a Lecidea belonging to tlie
(jyalectas, and only a microscopical examination makes its true relations
apparent. I t differs from the preceding in the colour of the thallus and
m tlie spores. The apothecia are sometimes not very well developed as
IS not uufrequently the case with lichens growing in similar situations’.
Hdi. On the ground in shady crevices of limestone rocks in upland
' ’ei-y sparingly in N.W. England.—B. Jl. : Haver-
brack Hill, W'estmoreland.
^ 6. C. diffundens Nyl. ex Cromb. Jo u rn . Lot. 1874, p. 3 3 2 .__
Thallus effuse, th in , areolato-squamulose, black, opaque ; squamules
subfurfiirous, small, variable. Apothecia small, inuate, somewhat
plane or often gyaleotoid, reddish, pale within ; spores ellipsoid,
0 ,0 1 1 -2 3 mm. long, 0,0 0 7 -1 1 mm. th ic k ; paraphyses slender, discrete
; hymenial gelatine bluish, then wine-red w ith iodine.—
Leight. Lich. El. ed. 3, p. 36.—Pyrenopsis diffundens Nyl. Flora,
1865, p. 6 0 2 ; Carroll, Jo u rn . Bot. 1866, p. 9 2 ; Cromb. Lich Brit
p. 3 ; Leight. Lich. FI. p. 16. Collema diffractvm Nyl. Carroll
Journ. Bot. 1865, p. 287.
The thallus and fructification sufficiently distinguish this from other
Bntish species. I have not seen an authentic specimen, and the plant
has been vainly searched for at Maidstone, Kent, where it was orio-inally
found. Specimens somewhat aberrant have been gathered elsewhere.
• f schistose rocks.—Dfstr. Very local and scarce
in S.E. England and N. W’ales.—B, AI. : Near Barmouth, Alerioneth-
shire.
7. C. lep to g ie lla Nyl. Flora, 1877, p. 2 20.—ThaUus effuse, thin,
minutely subeoralloideo-furfuraceous, olive-brown. Apotheoia lep-
togioid, minute, lurid-testaceous, slightly margined, tho epithe-
cium somewhat impressed or a t length subplane ; spores ellipsoid
or oblongo-ellipsoid, 0 ,0 1 0 -1 7 mm. long, 0 ,0 0 5 -7 mm. thick ;
paraphyses slender, or somewhat slender, thicker a t the apices ■
hymenial gelatine tawny wine-reddish with iodine.—Cromb Gro?
viUea, VI. p. 1 8 ; Leight. Lioh. Fl. ed. 3, p. 36.
This peculiai- species departs in various respects from the rest, and
belongs almost to a proper genus. The thallus is confusedly cellular,
with the gommia nearly moderate. The branchlets, which resembk
Hose oi Leptoymm min-oscopimm, Hough shorter, are subpapilliform.
In the only specimen seen by me, the apothecia are fairly numerous, the
margin being usually very thin.
'^"^'xPlL'luartzose rocks in upland districts.—Disir. Akry local and
rare m N.W. Ireland.—B. AI. : Kylemore, co. Galway.
Tribe H I . P Y R E N I D I E I Nyl. ex Cromb. Jo u rn . Bot. 1874,
p. 3 3 7 ; Flora, 1875, p. 103.
Thallus maculate, radiately appressed ; cortical layer d is tin c t;
gonimic granules moniliformly coherent. Apothecia pyrenoid;
spores 4iiEe, septate, b row n ; paraphyses soaroely any. Spermogones
unknown.
A singular tribe, holding amongst the Collemacei an analogous place
to the Pyrenodei amongst the Lichenacei. In this respect the family
very appropriately closes with it; for the genus Ohryzum, with its
pyrenoearpous apothecia, is now
known to be entirely parasitic, and
must be removed. The Pyrenidiei
consist of a single genus with a single
species; further research may
bring others to light.
19. PYRENIDIUM Nyl. Flora.
1865, p. 210.—Thallus minute,
stellato-divided, fibrillose. H e
cortical layer cellular, distinct.
Apotheoia innate, scarcely promin
en t; spores oblongo-ellipsoid, 3-
septate, b row n ish ; paraphyses
slender, few or obsolete; hymenial
gelatine no t tinged with
iodine.
Having regard only to He thallus,
this genus might be supposed
to be allied to Leptogium ; but the
form of He apothecia separates it entirely
from all the preceding genera
of the Collemei. There seems no
reason to doubt that the apothecia
really belong to the thallus and not
to a parasitic
Hg. 21.
Pyrenidium actinellum Nyl.—a. Thalline
filaments, x30. b. Transverse
section of a filament, x200. c. A
frustule of the cortex, X 350. d. Gonimia.
e,e'. Vertical sections of two
apothecia (viewed under water), X 30,
with a small portion of crustose
thallus. / . Theca with spores, X 350.
g. Two spores, XoOO.
1. p. actinellum Nyl. Flora, 1865, p. 210.—Thallus adnate,
thinly crustmform, th in ly stellato-fibriliose a t the circumference,
the fibrill® equally cylindrioal, sparingly brauohed, b u t usually
effuse, and entirely covered by or almost entirely composed of
somewhat erect fibrillaj, sordid- or dark-olive ( I - f wine-red). Apotheoia
minute, scarcely prominent, almost entirely innate, the
pyrenium entirely black ; spores 0 ,0 2 0 -2 4 mm. long, 0 ,0 0 8 -9 mm.
thick.—Carroll, in Jo u rn . Bot. 1866, p. 286 : Cromb. Lioh. Brit,
p. 1 0 ; Leight. Lioh. Fl. p. 36, ed. 3, p. 37.
The thallus of His species (of which I give Nylander’s emended
diagnosis) forms small maeulm on the substratum, which are more
or less scattered, or at length confluent. AVhen sterile it is externally
very similar to states of Leptoymm microscopicum; but under the
microscope its fibiillse are seen to be equally cylindrical, while in
a
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