geniculate at the joints. Capsule globose hyaline or pale hrown-
meinbraiious, dividing to about two-thirds into 4 valves, composed
of two layers, inner spongy. Elaters persistent at the apex of
the valves, usually unispiral.
1. Lejeunea Mackaii {Hook.), Spreng.
Jungermania Mackaii, Hook. Brit. Jung. t. S3 (1816).
Phragmicoma M ackaii, Dum. Comm. Bot. (1822).
Lejeanea Mackaii, Spreng. Syst. Veg. 4, p. 233 (1825-7).
Monoicous, densely but shallowly csespitose, small, reddish-
brown to blackish olive-green. Stems creeping, imbricate, firm,
more or less dichotomous, sometimes with only one innovation
proceeding from below the ? flower; cortical cells larger than
the inner, walls brown, 30-35, inner with pellucid walls 10 x 12.
Leaves imbricate, often densely, distichous, horizontal or patent-
divergent, unequally bilobed, antioal lobe slightly convex, sub-
semicordate, ovato-rotund, all very obtuse, postical lobe 3 to 4
times smaller than the antical, subquadrate or ovate, free
margin involute, bidentate, ventricose; cells smallish, 4-, 5- and
6-angled, walls thick, angles slightly thickened. Stipules twice
shorter than leaves, much wider than the stem, rotuiido-cuneate,
entire or retuse, never cordate or decurrent. Bracts unequally
bilobed, antical lobe ovato-obtuse, margin entire, postical from
half to one-third the size, oblong-obovate, margin entire. Bracteole
oval, apex retuse. Perianth projecting about half beyond tbe
bracts, obcordato-obovate, gibbous below, compressed, slightly
convex, mouth contracted, dentate, composed of a single layer ot
cells, about 150 round the middle. Capsule spherical, delicate,
whitish, dividing down to the base into 4 valves. Elaters
bispiral.
Andrcecia on long lateral branches not produced from the axil
of the leaves; perigonial bracts closely imbricate, smaller than
the stem leaves, subequally bilobed, antioal lobe oblong, postical
similar but slightly smaller, tu rg id ; antheridia two, large,
globose.
D im en s io n s .— S tem s J to 1 in c h lo n g , w ith le av e s 1 ’5 m m . to
2’ mm. wide, diameter of stem '15 mm. to '2 mm., leaves, antical
lobe 1'2 mm. x '9 mm., postical lobe -4 mm. x S mm., antical
1'2 mm. x 1' mm., postical "3 mm. x '25 mm., antioal '9 ro.m. x
■7 mm., postical '3 mm. x -2 mm. ; cells ’03 mm. x -02 mm., '025
mm. X "02 mm., '025 mm. x '025 mm., '035 mm. x '02 mm.;
stipules '6 mm. x '5 mm , '5 mm. x ’45 mm.; sub-hraot, antical
lobe 1'25 mm. x 1' mm., postical lobe '3 mm. x "I mm.; sub-
bracteole '7 mm. x -7 mm. ; bract, antical lobe I'o mm. x 1" mm.,
postical lobe 1' mm. x '45 mm.; bracteole 1' mm. x ’8 mm.;
perianth 1-3 mm. x 1'2 mm.; male branches 2 mm. to 6 mm.
long, 1- mm. wide ; perigonial bract, antical lobe 1' mm. x '6 mm.,
postical lobe '8 mm. x -4 mm. ; antheridia ’2 mm. x -175 mm.
H a b .—On shaded limestone and other rocks, in large or
small patches. Moderately rare.
1. Gulval Cam, Cornwall, J. Rnlfs. Eocks west of the
Lizard, Cornwall, W. Curnow. “ Common in Devon,” Hooker.
7. Barmouth, Dr. Carrington and W. H. P. Arthog, Merionethshire,
W. H. P. 10. Ingleboro, Yorks, Dr. Carrington. 12. Levens,
Westmorland, G. Stabler. Witherslaok, Westmorland, G.
Stabler. Lodore, Cumberland, W. H. P. 13. Eiver Dee, Tong-
land. New Galloway, J. McAndrew. 16. Invermoidart, West
Inverness, S. M. Macvicar. ■ I. Very common on the Soar Limestone,
Killarnej', Dr. Carrington. South of Ireland, Maekay, Dr.
Taylor, &c.
O b s .—Unlike other British Lejeunea in size and colour;
distinguished from Padules by presence of stipules and from
any of the British Frullanim by the entire stipules.
D esokiption of P late V II.—Fig. 1. Plant natural size.
2. Portion of stem, antioal view x 16. 8. Ditto, postical view
x 24. 4, 5. Leaves, postical view x 24. 6. Portion of leaf x 290.
7. Sub-bract x 16. 8. Sub-braoteole x 16. 9. Bract x 16.
10. Bracteole x 16. 11. Perianth x 16. 12. Cross-section of
perianth x 16. 13. Portion of male stem, postieal view x 24.
14. Perigonial bract x 24 (Arthog, W. H. P.).