segments, often beautifully fringed ; and the truncate tips finely cut. Tubercles
abundant, as large as poppy-seed, scattered along the margin of the
frond, both of the smaller and larger divisions. Tetraspores crowded in the
ultimate ramuli, on plants more slenderly branched than those that bear
tubercles. Colour a brilliant crimson-lake, becoming brighter in fresh water,
and at length discharged on long steeping. Substance membranaceous, soft,
adhering to paper in drying.
One of the rarest of the British Algse, almost confined with
us to the northern shores of Scotland, and the Orkney and
Shetland Islands, and in no place found in abundance. In
general British specimens are small, rarely attaining the size
of that represented in our plate, which is copied from the
largest of those presented to us by Messrs. Thomas and Mac
Bain. Most others which we possess are less than an inch in
length; some having deeply-cut fronds, like our Pig. 2, and
others comparatively little divided, like Pig. 3. All are, however,
but pygmies to the specimens collected on the east coast of
America, where this plant is as common as Plocamium coccineum
is with us, and to be found as invariably ornamenting the sea-
toeed pictures made by fair Bostonians as the latter is in those
manufactured at this side the Atlantic. On the American coast
B. cristata commences in the Arctic Sea, and extends southward
to Cape Cod (lat. 42°) where it suddenly disappears, as do also
several other northern species of marine plants and animals. In
Boston Bay it is peculiarly plentiful and of large size, and sports
in a number of varieties, some of which so closely resemble the
narrower and more delicate specimens of Spharococcus coronopi-
folius, that it requfres a practised eye to distinguish them without
an appeal to the dissecting knife.
The most southern point in Europe at which this plant has
been found is Berwick Bay (lat. 55° 45'), and there I believe it
has been taken but once. This affords a remarkable contrast to
its southern limit in America.
Fio-. 1 . U h o d y m b n i a c k i s t a t a :—natural size. 2 . A small frond, somealial.
magnified. 3. Another, of a broader variety. 4. Apices of laciniae with imbedded
tetraspores. 5. Tetraspores. 6. Section of a coccidium. 7. Spores.
8. Thin shoe, to show internal structure of the frond:—all magnified.
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