antheridia terminal or rarely situated at the middle of the stem ;
perigonial bracts little different from the others, slightly swollen
at the base and rather broader ; antheridia few, oval, the outer
layer persistent; bearers as long or longer than the antheridia
(some 12 cells long).
Fruits May, June.
Dij iexsions.— Stems | to inch long, '2 mm. diam., with
leaves '2 mm. to '3 mm. wide; leaves '9 nnn. long x 7 mm.
broad, '85 mm. x 7 min., 'G5 nnn. x '5 mm., segments '25 mm.
high X from '15 mm. to '4 mm. broad at the base; cells
•05 mm. X -025 mm., '04 mm. x 'Oo mm., '04 mm. x '02 mm.,
■03 mm. X -02 mm. ; marginal cells '02 mm. x '02 nnn. ;
trigones '0075 mm., bracts '9 mm. long x '7 mm. broad,
segments '2 mm,; pistillidia -15 nnn. long x -05 mm. broad,-
antheridia "25 mm. x '15 nnn.
IL\b.—Grows on e.xposed rocks in subalpine and alpine
localities. Not uncommon in North Wales, the Lake District,
and Scotland.
7. Cader Idris, Merionethshire, 7i'. J7. Holmes; IF . II. P .;
Cwm Bychan, Merionethshire, G.A. I lo lt; Llanberis and Snowdon,
Carnarvonshire, /'. M. Holmes, J. 11. Byrom, James Neild.
12. Harter Fell, Mardale, G. Si abler; Hill BeJl, / / . Marlindale
fl G. Stabler; Long Sleddale; Langdale, Westmorland, G.
Stabler. 15. Loch-na-gar, /. fl T. Sim. 16. Glen Finnan, I)r.
Carrington; Moidart, West Inverness, A. J7. Macvicar, rare on
low ground, hut descends to sea-level; common on the hills Ifom
1200 ft. to 2000 ft.
^ I. Mwellrea Mountains, Co. Mayo, Dr. D. Moore, 1874;
Slieve Donard and other mountains in the North, Bevs. Lett &
IF'iddell.
Found on the Continent.
O b s .— From Cesia concinnata (Lightf.) it may be distinguished
by its rounded, obtuse, finely crenulate segments, closely and
regularly imbricating leaves, bifariously inserted, never secund
(as Lindberg remarks).
Cesia crenulata (Gott.) is a widely different species, with finer
stems, arcuately branched, dark brown or almost black in colour^
in shaded situations greenish ; in this species the segments are
acute, with the hyaline fringe of leaf composed of narrow sharp-
pointed, irregularly projecting cells.
Cesia corallioides (Nees) has a more acute leaf, without sinus,
or if present, very shallow, or very irregular through being
weathered, and always has a very delicate diaphanous hyaline
border, so delicate that rarely any cellular structure is to be
observed. This character, along with the entire absence of any
approach to creuulation of the segments, at once separates it from
C. obtusa.
Cesia obtusa (Lindb.) was first recognised as British by
Mr. George Stabler and published in “ Journal of Botany ” for
1880.
D e s c r i p t i o n o e P l a t e CLXXIX.—Fig. 1. Plants nat. size.
2. Portion of stem x 64 (Cader Idris, E. M. Holmes).
3-7. Leaves x 31 (Glen Finnan, Dr. Carrington). 8, 9. Ditto x
31 (Scotland, Croall). 10. Lobes of leaf x 85 (Norway, Lindberg).
11. Portion of leaf x 290 (Glen Einnan, Dr. Carrington).
12, 13. Braots x 31 (ditto). 14, 15. Portions of the
innermost braots x 64 (Mardale, G. Stabler). 16. Bracteole x
64 (ditto).
9. Cesia crenulata (Gottsche).
Gymnomitrium crenulatum, Gottsche in Carrington’s Iri.sh Hepaticæ, Trans. Bot.
Soo. Edinb, vii. (18C3).
Acolea crenulata, Dum. Hep. Eu r. p. ]25 (1874).
Dioicous, densely cæspitose, tufts very dejtressed, small, of a
dark reddish or greenish brown or almost black colour. Stems
with about 20 cortical cells, reddish colour, 10 cells in diam. ;
intricately entangled, creeping, prostrate or suberect, arcuately
branched, filiform, wiry, catenulate, terete, or somewhat compressed
then lanceolate in outline ; radiculose, rootlets tew.
Leaves closely imbricate, erect, scarcely broader than the stem,
oval, ovate or broadly ovale, bidentate to about J, sometimes