Fig. 1 . Zostera marina, «. ; and Fig. 2. 0 . nat. size. Fig. 3. Portion of the extremity of a leaf of «. magnified.
Fig. 4. 4. Perfect anthers. Fig. 5. One laid open to' show the contents. Fig. 6. Pollen mixed with the
filament. Fig. 7. Old anther, with the opening whence the pollen has been discharged. Fig. 8. Germed;
and Fig. 9. Young seed taken from it. Fig. Id. Germen more advanced. Fig. 11 and 12. Seed-vessels
fully formed. Fig. 13. Young seed removed from the Germen at Fig. 10. Fig. 14. Ripe seed. Fig. 15.
Portion of its exterior integument. Fig. 16. Seed with the exterior integument removed, showing the embryo
within and the tubercle at the point of insertion. Fig..17. Portion of it§ internal tegument. Fig. 18. Embryo
deprived of its coverings. Fig. 19. Embryo laid open by force to show the insertion of the plumule and the
minute tuberculiform radicle at the extremity.—All from Fig. 3. more or less magnified.
Notwithstanding that the Zostera* marina is very common in our muddy æstuaries, and that it is thrown up
upon almost all our shores by the waves of the sea, its fructification is but little known. Mr. Wigg of Yarmouth
communicated flowering specimens from the neighbourhood of that town in April, and perfect seeds in ,the following
month, by means of which I am enabled to subjoin to .the accompanying figure a complete analysis of the
parts of fructification.
Various have been the opinions respecting the class of this plant in the Linnoean system. The great author of
it thought himself justified in placing it in Gynandria; but as Sir James Smith justly observes, “ the stamina
cannot in any sense be understood to grow out of the pistilla.” With more reason then others, among whom is
our countryman Withering, arranged it with Polyandria, considering the spadix as a receptacle for a number of
anthers ; in which circumstance there is nothing to militate against the definition of that class, although Sir James
Smith further remarks that “ they are not simply polyandrous, as in every such flower'the male organs are invariably
collected around the central collected females. He himself puts Zostera into Monandria and the order
Monogynia, and says that its fructification is easiest understood by considering.it as a simple unilateral spike of
naked flowers, disposed -in two ranks, that the anther of each is sessile; oblong, and a little curved, and that by its
side is affixed an oblong germen.:—I t is true, that by the side of each anther there is a germen ; but in all the species
that I have examined, the anthers exceed the germens generally in the proportion of two to one : that is to
say, in each of the two lines o f fructification there are, except to the uppermost and lowermost germens, two anthers
below each germen ; in which case, if the flowers could in any way be considered as separate, as Sir James
Smith intimates, Diandria Monogynia must be the class to which it should be.referred. If, however, the fructification
of this plant is not to be considered polyandrous, surely the class Moncecia, in which Willdenow and subsequent
authors have placed it, is the one to which it must naturally belong. Consequently, each anther and each
germen is regarded as a distinct flower attached to a spadix, without any perianthium whatever.
In the Natural Orders, Zostera has been put among the Aroidece by Jussieu and Decandolle ; and among the
“ Genera Aroideis affinia” by Mr. Brown, but reduced to the Fluviales, an order established by Adanson, by the
learned Richard, whose character for that order we have transcribed above. This, besides Zostera, contains Rup-
pia, Zannichellia and Potamogeton. They belong to a group of orders which Richard has denominated “ Endo-
rhizeef ; embryone epispermico ; ovario libero :|; ; ■ thus including such monocotyledonous plants as have a distinct
ovarium and an embryo without albumen, covered immediately by the integuments of the seed.
The structure of the anthers is highly curious, and, as far as my experience will enable me to speak,, very different
from the same organ in any other plant, but approaching nearest to Ckara and some species of Fucus. The
texture is in no wise different from the outer covering of the ovarium ; and even its figure is often so nearly the
same, that, were it not for the styles of the latter, they would scarcely be distinguishable from one another.
The representation of the structure of these seeds in Gærtner, de Fructibus, though generally correct, is. too
small to be satisfactory. Mirbel’s figures in the Annales du Muséum d'H'ist. Nat. are every thing that can be
desired, except that he (as well as Gærtner) has entirely overlooked the remarkable tubercle or swollen foot-stalk
to the embryo, which I have found in every seed that I have examined, but which does not appear even to be noticed
by any author, except it be what Richard alludes to, when he says, “ L’amande à\i Zostera est oblongue-
ovée, et offre à son bout supérieur une concavité dans laquelle est reçu un tubercule basilaire du Perisperme.”—
Analyse du Fruit, p . 64.
The smaller-sized specimens here figured are the most common. Indeed the larger one I have only found on
th e northern coasts of Scotland and in Iceland, where it grows abundantly at the mouths of the rivers and in the
bays ; but I never saw its fructification. Except in size the two agree in every particular. Even the three nerves
which are so conspicuous in the var. /3. are visible in «. by the help of a microscope, when held against the light.
When preserved, even with the utmost care, for the Herbarium, both kinds become black ; but when exposed
on the beach to the action o f the air and sun, they change almost to a pure white.
In the northern countries, where better materials of the sort are with difficulty procured, this plant is used for a
variety of oeconomical purposes. In Iceland I have seen it thrown into boxes to serve for beds. In Gothland,
according to Linnæus, the mattresses are stuffed with it in lieu o f hay ; and in other parts o f Sweden we learn from
the same author that houses are thatched with it, which will thus endure above a century ; chinks in stone walls
are stuffed with it instead of moss to exclude the cold air, and fields are manured with it. In Holland, where it
goes by the name of Weir, mounds or walls are formed of it to oppose the encroachment of the sea ; and Poiret,
m the Encyclopédie Botanique, tells us that it is employed in maritime countries for the purpose o f packing up bottles
and other brittle ware ; whence, he adds, the ancients have called it Alga Viirariorum.
* So called from Zaianjp, a lelt or girdle. . . . , , . . . . . . . . .
+ Professor Richard has written much on the subject of this kind of organization in the seed in his valuable, though m this country
little known, “ Analyse du Fruit," published at Paris in 1808. It will be sufficient in this place to transcribe his definition of it. “ En-
dorhixe, embryon dont la radicule, oulebas de la figelle, (partie de l’embryon qui unit la radicule au cotylédon simple ou multiplié,) renferme
le rudiment simple ou multiplié de la racine, qu’elle ne forme pas elle-même.”
t In the “ Proposition d’une Nouvelle Famille de Plantes; les Butomées."—Mém. du Muséum d'Hist. Nat. Ire Année.