x lA m m ., 2- min. x I'G mm., 2T mm. x 1'6 mm., 1'8 mm.x
17 mm., 17 mm. x 1’4 mm., 175 mm. x 1’5 mm.., postical
75 mm. X -4 mm., 7 mm. x -35 mm., '9 mm. x '5 mm.; cells
•035 mm. x '03 mm., ’035 mm. x ’025 mm., '035 ram. x '035 mm. ;
trigones '0017 mm.; stipules 75 mm. x -6 mm., 75 mm.x
75 mm. ; bract, antical lobe '8 mm. x '4 mm., postical '5 mm. x
25 mm. ; bracteole 7 mm. x -45 ram.; perianth 4'5 mm. x 175 mm.;
pistillidia -3 mm. X-075 mm.; capsule 1’2 mm. x '9 mm. ; perigonial
bracts, antioal lobe IT mm. x '6 mm., postical '85 mm. x
•4 mm., antioal 1' mm. x '55 mm., postical '55 mm. x '3 mm.;
perigonial bracteole '5 mm. x -3 mm.; antheridia T4 mm.x
'11 ram.
H ab.—On stones in rivers, or on rocks and trees by their side.
Somewhat rare, and extremely so in fruit.
1? 7? 10. On limestone rooks at edge of stream, Malham,
TF. Wed. On rocks near Collingham, W. Yorks, W. West.
12. Staveley, Westmorland, G. Stabler. High Lorton, Cumberland,
Rev. C. II. Biiistead. Ullswater, Cumberland, E. M. Holmes.
13. Near Kemnure Castle, New Galloway, .7. McAndrew. Balmao-
lennan, Dumfries, .1. McAndrew. On trees and rocks, Newtondon,
Berwioksliire, A. Brotherston.
I. On trees near Eiver Lagan, Co. Down, Rev. C. II.
Waddell. Continent.
Obs.—Difi'ers from P. platyphylla (L.) in its looser habit, more
distant leaves, planer, rather more dentate, smaller, narrower and
more contorted lobule, thinner texture, larger and distinct trigones,
smaller and more irregular stipules, smaller bracts, margin entire,
perianth with contracted month.
Porella pinnata (D.) is a muoli more slender specie.s, witli
more distant leaves, much smaller lobules and stipules, margins
of wliich are all quite entire.
D e s c r ip t io n op P l a t e XXXI.—Fig. 1. Plant natural size.
2. l°ortion of stem, antioal view X 11 (0. and P. n.). 3. Ditto,
postical view X 11 (ditto). 4,5. Leaves x 16 (ditto). 6. Lobule
X 24 (ditto). 7. Portion of leaf x 290 (ditto). 8. Stipule x 24
(ditto). 9. Bract X 24 (Sweden, S. 0. Lindberg). 10. Bracteole
X 24 (ditto). 11. Perianth x 11 (ditto). 12. Portion of mouth
of perianth x 64 (ditto). 13, 14. Perigonial bracts x 24 (ditto).
15. Perigonial bracteole x 24 (ditto). 16. Antheridium x 85
(ditto).
5. Porella p in n a ta (Bill.), Lindb.
.hmgermmiia Porella, Dicks. Trans. Linn. Soo. iii. p. 2.S9 (1797).
.hmgermania distans, Schwein. Musc. Hep. Amer. p. 9, n. 8 (1821).
.Jungermania Cordeana, Hüben. Hep. Germ. p. 291 (1834).
Madotheca Porella, Nees, Nat. Eur. Leb. .8, p. 201 (1838).
PoreUa p innata (Dill.) Lindb. Hep. Hib. Acta Soo. Sc. fenn. x. p. 493 (187.5).
Dioicous, laxly cæspitose, yellowish-brown to dark olive-green
in colour. Stems irregularly pinnate or subdichotomous, frontally
compressed, from 12 x 8 to 20 x 10 cells in diameter, cortical cells
very minute with thick walls and reddish-brown 50-80, the
2nd and 3rd outer layers usually the same, inner large, walls
hyaline. Leaves incubous, approximate or distant, unequally
bilobed, antical lobe plane or very slightly convex, ovate-oblong,
apices plane or indistinctly decurved, rotundate or obtuse, margin
entire, postical lobe or lobule minute, plane or slightly undulate,
a little decurrent, ereoto-patent, oblong, obtuse or obtusate,
margin entire ; texture delicate, thin, cells smallish, 4-, 5- and
6-angled, walls thin, trigones absent or very minute, marginal
cells with sliglitly thicker walls. Stipules appressed to the stem,
ovate-rectangular, rotundate-obtuse, plane, margin entire. Flowers
? on long or short lateral branches ; bracts smaller tlian the
stem leaves, unequally bilobed, somewhat carinate, antical lobe
oval, postical from -J- to smaller ; bracteole oval, apex rotundate.
Perianth (young) compressed, margins deeurved, convex antioally,
broadly ovate, moutli contracted, dentate. Pistillidia 6-8. Capsule
dividing to the base into 4 valves, bistratose, tlie outer layer
3, 4 times thicker than the inner.
D imensions.— Stem 1 to 2 inolies long, T5 mm. to '225 mm.
in diameter, with leaves 3' to 4’ mm. wide; leaves, antical lobe
1'6 mm. X 1- mm., 1'5 mm. x 1' mm., 2' mm. x 1'5 mm., U3 mm,
X ’8 mm., postical '6 mm. x '2 mm., '55 mm. x T25 mm., 7 mm. x
'3 ipm,, '8 mm. x '35 mm., '45 mm. x ’2 mm., '35 mm. x T75 mm. ;