prominent on the under surface. Stipules membranous,
whitish-green, soon disappearing, oblong. Spikes, cylindrical,
elongated, about an inch long, densely flowered, on
long, cylindrical, slightly thickened, straight or slightly
curved, solitary stalks, usually but not always rising above
the leaves. Nuts small, half as large as those of P . natans,
obliquely ovate; the back rounded and obtuse when fresh,
hut acutely keeled, with two less conspicuous lateral ridges,
when dry.
This beautiful plant inhabits deep peaty pits and ditches,
and is probably far from rare in such places. The specimens
figured were gathered in peat-pits in the Grande Mare, a
marshy district at Yazon Bay in Guernsey, in August, 1837,
by the writer of this, who has, since his return to England,
detected it in Sir J. E. Smith’s herbarium under the name
of “ P. natans,” from Diss, Norfolk, Mr. Turner, and S. of
Scotland, Dr. H. Thompson. He has also gathered it in the
fens of Cambridgeshire (1830). Mr. W. W. Sanders finds
it at Ham Ponds, Kent; Dr. R. D. Thomson, at Eerneyrig
Marsh, Berwickshire; and Mr. J. A. Power, at Roy den
Een, Norfolk. It has usually been confounded with P.
natans, from which it is distinguished by its beautifully diaphanous
reticulated leaves, none of which are coriaceous,
and its much smaller fruit. It is more nearly allied to P.
oblongus, from which its leaves, as well as the acutely keeled
back of its fruit when dry, clearly distinguish i t ; in that
plant the fruit is always obtuse.—C. C. B.