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REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 97
The plant is perennial and young specimens are entirely without perforations until they have attained
a length of two or three inches. The perforations, which are supposed by the fishermen to be the work of
animals, are formed in the lower part of the frond and increase in size as they grow older, so that the
perforations are larger in the upper and central parts of the frond. New holes are also formed between
those already formed, so that there is a difference in size depending upon the age of the holes in all
parts of the frond except the base. The formation of the holes begins by an elevation of small portions of
the frond, which appears as if some small point like that of a pencil had been pressed against it; at
length the frond ruptures circularly and the hole formed is minute and above the plane of the frond.
The margins of the large holes are often wavy, and when dried with a slight pressure the waviness
becomes so marked as to lead one to suppose that the specimens belong to a distinct species. The midrib
varies considerably in breadth and occasionaly [sic] it grows out, forming a lamina at right angles to
the frond. The usual perforations are found in the additional lamina, which sometimes grows to be as
large as the original lamina. The fruit of Agarum, which is incorrectly figured in the Nereis as having a
form of tetraspores, resembles very closely that of Laminaria. The species apparently does not bear
fruit on the Massachusetts coast, at least we have never been able to find any; but at East port the fruit
is formed as early as September. The sori are scattered irregularly over the central part of the frond
and are most easily seen after the frond has been out of the water a short time. The sori are not so thick
as in Alaria and Laminaria and the paraphyses do not have so prominent a hyaline extremity as in
those genera. Harvey states that the lamina are sometimes ten or twelve feet long, but this is probably
an overestimate.
ALARIA, Grev.
(From ala, a wing.)
Fronds attached by a branching root-like base, stipitate, membranaceous, with a
distinct midrib; fruit borne in special lateral leaflets below the lamina, consisting of
club shaped, one celled paraphyses and ellipsoidal unilocular sporangia; plurilocular
sporangia unknown.
A genus readily known by the small, ribless leaflets given off from the stipe below the lamina, in which
the the [sic] fruit is borne in the autumn. The genus inhabits the colder waters of the northern
hemisphere and the species sometimes attain a length of fifty feet. The number of species does not
exceed half a, dozen, and the specific marks, such as the shape of the midrib, the lateral leaflets, and
the base of the lamina, are variable, so that all the species cannot be said to be well marked.
A. ESCULENTA, Grev. (A. esculenta, Phyc. Brit., Pl. 79.—Laminaria musæfolia, De la
Pyl., Ann. Sci. Nat., Ser. 1, Vol. IV, Pl. 9 d.—L. linearis, De la Pyl., l. c., Pl. 9 f.)
Stipe cylindrical-compressed, from four inches to a foot long, a quarter to half an
inch wide; midrib solid, scarcely wider than the stipe; lamina one to ten feet long or
even longer, two to ten inches from side to side, decurrent on the stipe, margin wavy;
fructiferous leaflets numerouse [sic], shortly stipitate, three to eight inches long, half
an inch to two inches broad, linear-ovate or linear-spathulate.
Var. LATIFOLIA, Post. & Rupr. (Laminaria Pylaii, Bory, in Flore
S. Miss. 59——7