C. calcareous stones in upland situations.—Dfsti-. Very local in
b.W. England.—15. AI. : Near Cirencester, Gloucestershire.
rn.^ri ®®Lraderi Nyl. ex Cromb. Grevillea, xv. (1886) p. 12.—
Ih a llu s effuse, c®_spitoso-frutiouloso, somewhat erect, dichotomously
branched, dull olive-green or dark red d ish -b row n ; branches suh-
hn o a r irrogularly sulcato-rugose and somewhat angular, dilated in
the middle, constricted a t th e base and a t th e apices. Apotheoia
la te ra l small, concave, reddish, the margin entire, paler ; spores
ellipsoid, 3-5-sep tate and siibmiirali-divided, 0 ,0 2 3 -3 3 mm. long
0 ,0 1 1 -1 5 mm. Leptogium Schraderi Aludd, Alan. p. 4 9 -
Cromb. Lioh. Brit. p. 9 ; Leight. Lioh. EL- p. 36, ed. 3, p. 3 d ’
I olyelmUum Schraderi Gray, Nat. Arr. i. p. 402. Oollema Schraderi
Eng. Bot. t 2 2 8 4 ; Sm. Eng. El. v. p. 213. Lichen Schraderi
Bernh in Schrad. Journ. i. (1799) p. 22, t. 2. f. 5 .— B r it. Exs. ■.
Larb. Lich. Hb. n. 4.
This usually forms small tufts which shrivel up very much in a dry
Z Z Z hV u ® yliicli are at first appressed, become nearly
erect and festigiate at the apices, being paler at the base. I t has mouili-
torin gommia. I t is rarely seen fertile, aud the apotbecia are few.
ILab. On cretaceous and calcareous soil, rarely on the mortar of old
walls 111 maritime and upland situations.—Disfr. General, thouo-h no-
i b r ^ A ^ ^ Q Eugland (chiefly in the S.), very rare amongst
the UAV. Grampians Scot and, and rare in the Channel Islands, in N.
mid S. Ireland.—B.AL : Island of Ilerm ; Alouliii Ilu et, Island of Giiern-
sev. Caistor Church Norfolk; Alartham, Suffolk; Shiere, Surrey;
Shankhn, Isle of W ig h t; The Downs and near Brighton, Sussex; Bab-
bicombe and near Plymou^th, S. Devon ; St. Alinver, Cornwall; Cheddai-
Ohtts and Bathampton Downs, Somersetshire; near Siddiiigton, Gloucestershire;
Miller s Dale, Derbyshire ; Island of Anglesea, N. Wales ;
near Aliffithorpe Westmoreland Appin, Argyleshire; Glen Lyon, Perth-
Eterr' Killarney, and Dunkerron, co.
K e rry ; Dawros^ co. Galway; Sheep Walk, co. Armagh.
16 LEPTOGIUM Gray, Nat. Arr. i. (1821) p. 395 ; Nyl. Mem.
Soo. Cherb. (185o) p. 165, emend.—ThaUus m icrophylline, fruticulose
or rarely granulose, sometimes foliaceous and macrophylline internaUy
ceUular or w ith tu b u la r interwoven c av itie s; gonimia more
or less monUiform; cortical layer more or less distinct, usually
formed of a simple series of cells. Apotheoia lecanorine or biatoroid •
spores 8nse, more or less oblong, variously septate and divided’
colourless : hymenial gelatine deep blue with iodine. Spermo"-ones
immersed, w ith shortly articulate sterigmata and stra ig h t spermatia
ohsoletely incrassate a t both apices.
As now limited, this genus, though better defined than formerly, is
still closely related to Collema. I t is distinguished by the thaUus in the
foliaceous species being thinner and less turgid when moist, bv the ano-
thecia being often biatoroid, and more especially by having'a distinct
cortical layer, though sometimes entirely cellular within. The snermn
goues. as m and Coljnodium, hme the spermatia identical in
size, viz. 0,003o-0,0040 mm. long, scarcely 0,001 mm. thick. Aceordincto
the anatomical structure of the thallus and the cliaracter of the apothecia,
it is divided by Nylander into four subgenera, all of which occur in
our Islands.
Subgen. HOMODIUM Nyl. Elora, 1875, p. 297 {cfr. Cromb.
Grevillea, xv. p. 12).—ThaUus miorophylline, granuloso, or variously
lohed or frutioulose, entirely ceUular within ; gonimia rarely in p a rt
moniliform. Apotheoia urceolate or biatoroid; spores variously
septate and divided.
1/ ' I
I'l
I '
Pig. 15.
Leptogium tenuissimum Koerb.—a. Thalline laciniæ, x30. h. Transverse
section of thallus, x200. c. Section of apothecium (when dry), x30.
d. Spores, X500.
Fig. 16.
Leptogium muscicola Fr.—a. Thalline branch, xSO. a'. Branehlet with a
spermogone, XSO. h. Transverse and longitudinal sections of thallus, X200.
c. Spores, x500. d. Sterigmata and spermatia, x500.
'M