The English flora - SeaweedAfrica

Diphyscium.] MUSCI-ACROCARPI-PERISTOMI. 13
stand in rows from the centre to the circumference, so that when any
part of the lid is obliquely placed, with respect to the eye, the partitions
of the cells, in perspective, represent dark lines resembling radii; and
this appearance is so constant when the lower or concave side of the lid
is uppermost, in every part but that which may happen to be turned at
right-angles to the line of sight, that it is no wonder that Hedwig and
others believed in a fissile lid. The top of the columella always adheres
to the lid, and it is not easy to remove it. I made several longitudinal
sections in order to ascertain the texture of the lid, and always found
it to consist of the spongy body lining the concavity, and, on its removal,
an arch of pyramidal cells extending quite through the lid, without in-
terruption, thus proving the non-existence of a peristome.—These sections
were allowed to dry under the microscope, and in an instant the
spongy portion of the columella shrunk up and disappeared, the diameter
of the lid became very much less : the concave side became plane, and
the upper or convex one was increased in convexity ; the thickness not
visibly altered, except so far as the spongy lining was in question. On
the application of water the original shape was restored. I may add
that when the Schistostega is in its infancy, it resembles a conferva with
globular articulations :—in this state it constitutes the " shining moss"
or " golden-green light,''' described by Mr. Bowman in the Mag. of Nat.
Hist. (v. 3. p. 462.). Of this fact I am well assured, having carefully
examined young half-developed plants possessing confervoid branches,
connected with the base of the stem."
Subsect. III. Lid deciduous. Mouth of the capsule furnished
with a peristoma. Peristomi. 1
Div. I. Peristome single. Aploperistomi.'-
8. Diphyscium. Mohr. Diphyscium.
Seta terminal. Capsule gibbous. Peristome single, forming a
plicate membranous truncated cone. Cali/pha mitriform. (Muse.
Brit. t. 1.).—Name, 2< ? , twice, or two-fold, and $-j«xrh a bladder,
from the double membrane of which the capsule is composed.
To mr this appears to be with great justice separated from
Buxbaumia by Mohr: and differing as it does in its foliage, as
well as peristome, from that Genus, I cannot but be surprised
thai Schwaegrichen, in his Sj>. Muse. Frondowrum, should
have united them.
1. D. folidsum, Mohr, (leafy Dipfyscivm), Mohr, l>s. Hot.
Muse. Scot.
p. 34. Hook, in II. Loud. X. S. cum I< . thrum.
r. 1. //. 6.— Buxbaumia foliosa, Linn. Syst. Veget, p. 945.
11. lint. p.
I I is. /•;. Hot. t. 329. Dill. Muse. /. 82./ 13.
\\ ods, oo banks and wall-tops, in alpine situations. Fr. Summer.
A minute plant, densely tufted. Stems none. Leave* small, ligulate
rue
ami entire, dark-green, opaque, furnished with a strong nerve. Ft
iijfra/inu large in proportion to the size of the plant," enveloped by the
perichsetial leaves, which arc lanceolato-oblong, membranaceous, acuminated,
jagged at the extremity, having a strong, rigid, brown, excuxrent
nerve. Captule nearly sessile, ovate, oblique, gibbous. Calyptra mitriform.
/.