S 2 [ 2253 ]
TETRANDRIA Tetragynia.
Gen. C h a r . Cal. n o n e . Petals 4 . Style non e . Seeds 4.
S p e c . C h a r . Leaves linear-lanceolate, alternate, sessile,
broader than their stipula. Stem round,
somewhat forked.
S y n . Potamogeton gramineum. L in n . Sp. P I. 1 8 4 .
Sm. F l. B rit. 1 9 6 . Huds. 7 6 . With. 2 1 4 . H ull,
ed. 2 . 4 9 .
P. gramineum latiusculum, foliis et ramificationibus
densissimè stipatis, D ill, in R aii Syn. 1 4 9 . t. 4 . / . 3.
Dii LjENIUS mentions this as growing in ditches, near
Deptford. W e have a specimen from Mr, Rose’s herbarium.
That in our plate was .gathered near Beverley, Yorkshire, by
the late Mr. R. Teesdale. It is a species which few botanists
seem to have ascertained, but we can see no obscurity about it.
The whole herb grows under water, except the spikes, which
in July rise above the surface. The root is perennial. Stem
slender, round, zigzag, much branched, and partly forked.
Leaves grassy, alternate, except at the forks, spreading,
crowded, linear, bluntish, entire. Stipulas rolled inwards cy-
lindrically, and thence most of them, at least in the lower
part of the stem, narrower than the leaves, all pale brown or
whitish. Spikes ovate, dense, solitary, of few flowers, from
the forks of the stem, except some of the upper ones, each
standing on a swelling stalk of its own length.
Lightfoot justly complains that the plate of Dillenius in
Ra y’s Synopsis wants the stipulas, but his own P . gramineum
is not this plant. W e have ventured to cite it, and the figure
in FI. Dan. t. 222, which he commends, as one state of our
heterophyllum, t. 1285.