Plant submerged. Stem solid, round, several feet long,
branching and rooting irreghlarly and at distant points, with
many closely placed whorls, in threes, of oblong bluntly
pointed minutely serrulate diaphanous leaves, which spread
at right angles to the stem. Occasionally only two opposite
leaves are present, and very rarely (from the observations of
Mr. Salter) a larger number than 3 is found in a whorl. The
flower springs from the axil of a leaf-like bract, which is placed
singly within and above the whorl of leaves. It is inclosed in
a tubular bifid spath, has a sessile germen, and an exceedingly
long tubular perianth ending in six lobes, 3 manifestly representing
a calyx and 3 a corolla. Sepals concave, boat-like,
thin, smooth, incurved. Petals very thin, flat, minutely
rough, reflexed. Both are of a pale pink colour. Filaments
linear, flat, blunt, incurved, totally without anthers. Style
adnate to the tube of the perianth on three sides. Stigmas 3,
ligulate, often bifid, fringed, reflexed. Fruit unknown in
Britain; but we have given a representation of the young
ovary and ovules (f .Sa, b). The flowTers are raised to the
surface of the water by their long tubes, and float there like
little pink spangles. They are produced in abundance during
the latter part of the summer. The male flowers are stated
to be sessile and without a tube, and to break off at maturity,
as do those of Vallisneria. They are rarely seen, even in
America.
This is not a fit place in which to discuss the nomenclature;
but we consider Elodea and Anacharis to be distinct genera,
and that our plant certainly belongs to the latter. The
specific name is more open to objection, as there is a Udora
canadensis of Nuttall, which may be the same plant as our
Anacharis. But there is also an Elodea canadensis (Michx.)
which can hardly be the same species as our A. Alsinastrum,
for it has very narrow leaves; and as it is an Anacharis, our
plant, if distinct, cannot bear the name of A. canadensis. An
authentic specimen of Nuttall’s U. canadensis seems to be the
same as the plant of Michaux, and is exceedingly unlike our
present subject.
The principal figure on the plate is taken from specimens
gathered near Market Harborough in October 1847: the
remainder, as also the details of the flowers, from cultivated
plants communicated by the writer and the late Mr. Borrer,
in June and August 1848.
Fig. 1. Market Harborough plant. Figs. 2 & 3. From
Mr. Borrer’s garden. Figs. 4 & 5. Base of flower and spath.
Fig. 6. Flow'er-bud. Fig. 7- Flower much magnified: a,
section of tube of perianth and style; b, flower; c, petal; d,
cells producing the roughness of the petal. Fig. 8. a, vertical
section of ovary with ovules ; b, ovules. Fig. 9. Leaves and
their tissue. Figs. 1, 2, and 3 are of the natural size; the
others are all magnified, and chiefly derived from drawings
made in 1848 by Mr. J. He C. Sowerby.—.0. C. B.