or ligulate, margin recurved and entire (fig. 43).
Calyx ovate, compressed and flat, then erect, cylindrical,
mouth truncate, serrate, deep notch on one
side, half its length (figs. 44, 45). Capsule pale
yellow brown. Elaters bispiral.— 2, fig. 18 )
Porella rivularis, N.
Branches simply pinnate, leaves entire,
ovate, obtuse, decurved, shor t ly auriculate,
aur icule somet imes discrete, st ipules semi;
lunate, decurrent. Perianth two-lipped, mouth
crenate.
Madotheca rivularis, Ne e s Enr. Leb. 3, p.
19 6 ; Gott. and Rab. Exs. No. 3 7 1 ; Cooke
Hep. i. 142. Porella rivularis, Carr, and
Pears. Exs. 131.
On stones in streams.
Tufts wide, loose, dark green, the younger
shoots o f a lively green.
Stern, i to 2 inches long,
irregularly branched, scarcely
pinnate, branches short, patent.
Leaves oblong-rounded, sometimes
a little narrower at the
top, quite entire (fig. 46), their
structure densely and minutely
cellular. The lower lobe is
more minute, in proportion to
the upper, than in any o f its
congeners, the stipules are
scarcely wider than the stem.— Tayior [Plate 2
f k - i 9 -) ■ ■
Porella thuja, Dicks.
Cæspi tose, stem ascending, subpinnately
branched, above convex, smooth, leaves c losely
imbricated, lowe r lobe spreading, elongated,
recurved, ent ire; interior ovate, rather obtuse,
margin reflexed; st ipules oblong, acute, entire,
margin reflexed, recurved at the apex ; peri-
chætial lateral, emergent, leaves larg er ,c il iately
serrate.
Jungermannia thuja, Dicks. Crypt . 4, p. 19;
T a y lo r T ran s . Bot. Soc. Edin. II., 116.
Madotheca thuja, Dumort . Comm., p. i i i .
Porella thuja, Carr, and Pears. Exs. No. 46.
Jungermannia platyphylla v. thuja. Hook.
Jung. t. 40, fig.
On stones by lake sides.
Tufts wide, olive green, the older parts purplish
brown, shining, the shoots acuminated. In plants
with perichætia the branches are very short. It may
be known from P . platyphylla by its greater size, its
shining surface, its acuminate shoots, its denser
structure, its perichætia prominent beyond the stem
leaves, its perichætial leaves larger, wider, more divergent,
and always ciliately-serrate, its divisions less
regularly pinnate, the closer imbrication o f the
leaves, and the more patent position o f their
inferior lobes.— Taylor. {Plate 2, fig. 20.)
Porella pinnata, Lind.
Stems ir regula r ly pinnate, or subdichoto