broken up b y deep pits communicat ing with
the air-cavities. L a rg e r and l ighter coloured
than R . glauca.
Riccia crystallina, Linn. Sp, 1605 ; Cooke
Hep. fig. 200; Lindenb. Mon. 437, t. xxii.,
fig. 2.
On banks and hedges on damp mould.
var. a vulgaris. Fronds less deeply cut,
lobes obcordate, margin rather elevated,
crenate.
Riccia pellucida, Hoffm. Germ. 96 .— {Plate 7,
fig- 9 4 )-
var. j3 palustris. P’ronds with linear laciniae,
apex less dilated, c renulately emarginate.
Riccia crystallina (3, Hook. Muse. Brit. 212 ;
Eng. FI. V., I, p. 98 ; Lind. Mon. t. xxii.,
fig. 2. No. 9. Lichen palustris. Dill. Muse. 355,
t. 78, f. 12 .— [Plate 7, fig . 94b.)
Grows in more shady and moist situations than
R. glauca, has the frond
generally longer, broader, and
much thinner, nearly plane,
with the segments more
numerous, and very obtuse,
colour by no means glaucous,
rather perhaps inclin-
' 96- ing to yellowish green.
Fronds in orbicular tufts radiating from the centre,
when fresh of a remarkably crystalline appearance.
Riccia glaucescens, Carr.
Frond fiabellate-furcate, segments linear,
wedge-shaped, concave, with rather a broad
border, margins thinner, fringed with small
translucent cells, not channelled above, pale
glaucous, apex emarginate ; under surface
purplish.
Riccia glaucescens, Carr, in Carr, and Pears.
Exs. No. 66.
On moist ground.
Dioicous. Fronds fiabellate-furcate, sometimes
crowded and imbricate, segments linear, cuneate,
or battledore-shaped, concave, not channelled on
the upper side, surrounded by a rather broad border,
recurved and convex when moist, inflexed
when dry, texture homogeneous, composed of large
cells, arranged in regular series, thickened along
the mid line of the lower surface; margins thinner,
acute, fringed with small but strong translucent
cells, sometimes wanting or irregularly disposed,
and the border simply crenulate. A p e x of the
fronds emarginate, lobes connivent, connected at
the base by a lunate fold, between which there
is often a small central tongue proceeding from
the inferior lobe of the frond. Colour pale translucent,
glaucous green above, border somewhat
paler, under surface covered laterally by a delicate
membrane, or detached scales of a purple colour.
Capsules few, occupying the hollow central channel
near the base of the frond. Spores large, dark
brown, muriculate.— [Plate 7, fig. 87.)