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132
THE MARINE ALGÆ OF NEW ENGLAND.
Common from Nantucket southward.
A summer plant which attains perfection during the month of July, disappearing later in the summer.
It is sometimes found washed ashore in large quantities after a storm. The species has been known for
some time, but until recently it has passed for a form of G. corallina, a species common in Europe. It
differs from that species in several respects. The antheridia form a sort of cap over the top of the
terminal cells of the male plant, which is considerably smaller than the female plant and has a
different habit, in consequence of which it was called a variety, var. globifera, by Harvey. The female
and tetrasporic plants more closely resemble the true G. corallina. They do not end in large globose
cells, as in the male plant, but the largest cells are below the tip, which is tapering and acute. When the
tetrasporic plant has narrower and more acute cells than usual it constitutes the var. tenuis of the
Nereis. The slenderest specimens, however, are usually sterile. In the structure of the procarp this
species differs considerably from G. corallina as described by Janczewski. There is only one trichogyne
instead of two, as in the last-named species. The procarp begins by the growth of a hemispherical cell at
the upper part of an articulation. The cell is then divided into two parts by a partition parallel to the
base. It is from the lower cell thus formed that the involucre is formed, and from the upper arise the
carpogenic cells in the following way: By usually four oblique partitions there are formed four external
hemispherical cells and a central pyramidal cell with a broad base. By subsequent division of one of the
hemispherical cells, generally of the one lying nearest the axis of the plant, there is cut off a cell which
divides into three smaller granular cells, the upper of which grows into a trichogyne. The spores are
formed by the subsequent growth of the other three hemispherical cells. There are two sets of hair-like
organs which arise from the upper border of the cells in this species; one set is short and granular,
consisting of a cuboidal basal cell with short corymbose filaments; the other set occupies a similar
position, but the hairs are long and hyaline, consisting of a long basal cell, which bears at its apex a
whorl of three or more cells, which in turn bear other whorls, the whole hair being several times
compound.
HALURUS, Kütz.
(From αλς [als], salt, and ουρα [oura], a tail.)
Fronds monosiphonous, branching, beset throughout with short, approximate,
incurved, di-trichotomous, whorled, secondary branches; tetraspores tripartite,
attached to the inner side of special branches, arranged in whorls one above another;
antheridia in similar position, forming closely verticillate tufts; favellæ terminal on
short branches.
A genus composed of one, or according to some writers two, species, separated from Griffithsia
principally by the character of the frond.
H. EQUISETIFOLIUS, Kütz. (Griffithsia equisetifolia, Ag.; Phyc. Brit., Pl. 67.)
Fronds four to eight inches long, arising from a disk, irregularly branching,
secondary branches trichotomous below, dichotomous above, much incurved, densely
covering the branches, rhizoidal descending filaments given off from some of the
lower branches.
Brooklyn, N.Y.?
A plant resembling a Cladostephus, except that its color is a dirty red. The species is very doubtfully
known on our coast. It is mentioned in the Nereis as having been sent to Harvey by Mr. Hooper, of
Brooklyn, but there is no definite information as to the locality where the plant was collected.