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92
THE MARINE ALGÆ OF NEW ENGLAND.
LAMINARIA, Lamx.—Devil’s Aprons.
(From lamina, a plate.)
Fronds attached by a branching base,* stipitate, stipe expanding into a ribless entire
or laciniate lamina; fruit forming bands or sori in the central part of the lamina,
consisting of unicellular paraphyses and unilocular sporangia densely packed
together; cryptostomata wanting.
A genus comprising not far from twenty-five species, which inhabit principally seas in high latitudes.
They all grow in pools at low-water mark and in deep water, and some attain a very large size. The
limits of the genus are well fixed, but the same can by no means be said of the species, with regard to
which writers differ very much. The difficulty arises partly from the fact that the species lose some of
their characteristic marks in drying, so that the study of herbarium specimens is unsatisfactory, but
still more from the fact that the species vary greatly in outline and habit according to the season and
the place of growth, whether at an exposed or sheltered coast or whether submerged or partly exposed
at low tide. In general, the species may be classed in two groups, those in which the frond is ribbon-like,
that is, long in proportion to the breadth and not split up into segments, and those in which the frond is
proportionately broader and fan-shaped and, except when young, laciniate. To the former group belongs
the L. saccharina of older writers, to the latter L. digitata, and it is with regard to the extent to which
subdivision shall be carried in the two cases mentioned that recent writers differ very widely. Our
species have not been sufficiently studied in situ to warrant us in giving the determinations with any
degree of confidence. More information with regard to their winter condition is very much needed. The
most detailed account of the Laminariæ of the eastern coast is to be found in the paper of De la Pylaie
in the Annales des Sciences Naturelles, Ser. 1, Vol. IV, 1824, entitled “Quelques observations sur les
productions de File de Terre-Neuve, et sur quelques algues de la côte de France appartenant au genre
Laminaire.” The article is accompanied by a plate in which is sufficiently well shown the habit of our
common species. The same writer in 1829 gave a more extended account of his collections in the “Flore
de Terre-Neuve et des lies Saint Pierre et Miclon,” an incomplete work comprehending the
Laminariaceæ and Fucaceæ, of which, however, the plates were never published. The species of De la
Pylaie have not been accepted without question by algologists, and all agree that he was too liberal in
the formation of new species. Harvey ignores the greater part of them in the Nereis. Agardh and Le
Jolis give them a more respectful consideration, and the former especially is inclined, in his paper on
the Laminariaceæ and Fucaceæ of Greenland, to admit several of De la Pylaie’s species. In the present
case we do not feel at liberty to make use of the notes with regard to American forms which have been
kindly furnished by European correspondents, but must content ourselves with a superficial account of
the perplexing forms of this exasperating genus, adding that the identity of our forms with those of
Europe is not in all cases proved.
Of the species of Laminaria given in the Nereis, L. fascia in now placed in Phyllitis; L. lorea and L.
dermatodea refer to the same plant, which is now placed in Saccorhiza; L. longicruris is still kept as in
the Nereis; L. saccharina and L. digitata are kept with limitations; and L. trilaminata is, as Harvey
suspected, merely an abnormal winged form of some other species, corresponding to the trilaminate
condition mentioned under Agarum Turneri.
The marks used in distinguishing the species are the arrangment [sic] of the root-fibers; the structure
of the stipe, whether solid or hollow, whether provided with distinct cavities containing mucus
(muciparous glands) the shape of the lamina, more particularly
*A few species, as L. solidungula, Ag., have a disk-like base, and L. sessilis, Ag., including L. apoda,
Harv., found on our west coast, has no stipe properly speaking.