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THE MARINE ALGÆ OF NEW ENGLAND.
articulated; antheridia, carpospores, and tetraspores borne in distinct cavities
(conceptacles), which are either external or immersed in the fronds; antherozoids
spherical, attenuated at one end, or provided with two short projections borne on
short filaments at the base of the male conceptacles; carpospores pyriform,
terminating short filaments which surround a tuft of paraphyses at the base of the
female conceptacles; tetraspores zonate, occasionally binate.
The present order includes all the calcareous Florideæ except a comparatively few species which belong
to the Nemalieæ and Squamarieæ. Although classed by the earlier writers with the corals rather than
plants, the species of Corallineæ are now placed at the head of the Florideæ, in consequence of their
highly differentiated organs of fructification. Our knowledge of the fructification of the Corallineæ is
derived principally from the Études Phycologiques of Thuret and Bornet and the Recherches
Anatomiques sur les Melobésiées of Rosanoff. Thuret and Bornet describe three different forms of
conceptacle, containing, respectively, the antheridia, the carpospores, and the tetraspores, the last only
being mentioned by Harvey in the Nereis. The tetraspores, which are much more common than the
carpospores, are usually zonate, although occasionally binate, and from the fact that they are borne in
distinct conceptacles, which is not the case with the other Florideæ, it had erroneously been considered
that the carpospores of the Corallineæ were four-parted. The cystocarpic spores, or carpospores, are
always pyriform and undivided, and accompanied by paraphyses. The number of trichogynes is large,
and they project in a tuft at the orifice of the conceptacle at the time of fertilization. The antherozoids
differ from those of the other Florideæ in having appendages.
The Corallineæ abound in the tropics, and but few representatives are found in northern seas. Our own
coast is especially poor in species. The study of the development of the plants of this order is difficult,
owing to the calcareous deposit, and soaking in acid injures the more delicate parts. The species are
nearly all fragile when dried, and it is not easy to preserve herbarium specimens in good condition. The
suborder may be divided into two tribes. The Corallineæ proper have articulated fronds, which rise
vertically from the substratum, as is seen in our common Coralline. The Melobesieæ are not articulated,
but form irregular horizontal crusts, which sometimes rise in irregular erect branches.
Fronds erect, filiform, articulated .......................................................Corallina.
Fronds horizontally expanded or vertical and inarticulate.
Fronds horizontal .............................................................................. Melobesia.
Fronds rising in irregular protuberances from a horizontal base,
........................................................................................Lithothamnion.
CORALLINA, Lam.x.
(From κοραλλιον [korallion], a coral.)
Monœcious or diœcious, fronds arising either from a calcareous disk or from
interlaced filaments, erect, terete or compressed, articulated, branched, branches
opposite, pinnate; conceptacles terminal, naked or occasionally with two horn-like
appendages.
A genus comprising about thirty to thirty-five species, mostly tropical, C. officinalis, C. squamata, and
a few others extending high northward. The fronds of Corallina are formed of a bundle of dichotomous
parallel filaments, whose external branches grow