62 COLLEMACEL. [conLEMODIUM. 
Hab. On calcareous stones in upland situations.—Distr, Very local in 
S.W. England.—B. M.: Near Cirencester, Gloucestershire. 
8. C. Schraderi Nyl. ex Cromb. Grevillea, xv. (1886) p. 12.— 
Thallus effuse, caespitoso-fruticulose, somewhat erect, dichotomously 
branched, dull olive-green or dark reddish-brown; branches sub- 
linear, irregularly sulcato-rugose and somewhat angular, dilated in 
the middle, coustricted at the base and at the apices. Apothecia 
lateral, small, concave, reddish, the margin entire, paler: spores 
ellipsoid, 3-5-septate and submurali-divided, 0,023-33 mm. long, 
0,011-15 mm. thick.—Leptogium Schraderi Mudd, Man. p. 49; 
Cromb. Lich. Brit. p. 9; Leight. Lich. Fl. p. 36, ed. 3, p. 34. 
Polychidium Schraderi Gray, Nat. Arr. i.p.402. Collema Schraderi 
Eng. Bot. t. 2284; Sm. Eng. Fl. v. p. 213. Lichen Schraderi 
Bernh. in Schrad. Journ. i. (1799) p. 22, t. 2. f. 5.— Brit. Exs, : 
Larb. Lich. Hb. n. 4. 
This usually forms small tufts which shrivel up very much in a dry 
condition. The branches, which are at first appressed, become nearly 
erect and fastigiate at the apices, being paler at the base. It has monili- 
form gonimia. It is rarely seen fertile, and the apothecia are few. 
Hab. On cretaceous and calcareous soil, rarely on the mortar of old 
walls in maritime and upland situations.—Distr. General, though no- 
where very common in England (chiefly in the 8.), very rare amongst 
the S.W. Grampians, Scotland, and rare in the Channel Islands, in N. 
and 8. Ireland—B. M. ; Island of Herm ; Moulin Huet, Island of Guern- 
sey. Caistor Church, Norfolk; Martham, Suffolk; Shiere, Surrey; 
Shanklin, Isle of Wight; The Downs and near Brighton, Sussex; Bab- 
bicombe and near Plymouth, 8. Devon; St. Minver, Cornwall; Cheddar 
Cliffs and Bathampton Downs, Somersetshire; near Siddington, Glou- 
cestershire; Miller’s Dale, Derbyshire ; Island of Anglesea, N. Wales; 
near Milnthorpe, Westmoreland. Appin, Argyleshire ; Glen Lyon, Perth- 
shire. Blackrock, near Cork; Muckross, Killarney, and Dunkerron, co. 
Kerry ; Dawros, co. Galway ; Sheep Walk, co. Armagh. 
16. LEPTOGIUM Gray, Nat. Arr. i. (1821) p. 395; Nyl. Mém. 
Soc. Cherb. (1855) p. 165, emend.—Thallus microphylline, fruticulose 
or rarely granulose, sometimes foliaceous and macrophylline, in- 
ternally cellular or with tubular interwoven cavities; gonimia more 
or less moniliform ; cortical layer more or less distinct, usually 
‘formed of a simple series of cells. Apothecia lecanorine or biatoroid ; 
spores 8ne, more or less oblong, variously septate and divided, 
colourless ; hymenial gelatine deep blue with iodine. Spermogones 
immersed, with shortly articulate sterigmata and straight spermatia 
obsoletely incrassate at both apices. 
As now limited, this genus, though better defined than formerly, is 
still closely related to Codlema. It is distinguished by the thallus in’ the 
foliaceous species being thinner and less turgid when moist, by the apo- 
thecia being often biatoroid, and more especially by having a distinct 
cortical layer, though sometimes entirely cellular within. The spermo- 
gones, as in Collema and Collemodium, have the spermatia identical in 
size, viz. 0,0035-0,0040 mm. long, scarcely 0,001 mw. thick. According 
