50 ENGLISH BOTANY. 
Leaves all similar, sessile and semiamplexicaul, narrowly linear, very 
slightly narrowed towards the base, subacute or subobtuse, with 3 
(rarely only 1) longitudinal ribs without fainter ones between them, 
mostly without axillary fascicles of leaves. Stipules small, subacute, 
subscarious, with numerous slender longitudinal fibres. Peduneles | 
termina between the forks of the stem, longer than the stem (usually 
twice as long, or even more), filiform, not thickened upwards. Sepals 
with their lamina suborbicular. Pistils 4. Fruiting-spike oblong- 
ovoid, not interrupted, few-flowered. Fruit small, greenish-olive, . 
scarcely compressed, acuminated, convex on the upper margin, on 
which there is no tooth, half oval-obovate and very bluntly 3-keeled — 
on the back, terminated by a rather short, central, slightly recurved | 
beak. Plant rather dull deep green, becoming darker when dried, ; 
> > 
Var. a, vulgaris. ' 
Piate MCCCCXIX. 
Reich. Ic. Fl. Germ. et Hely. Vol. VII. Tab. XXTI, Fig. 38, 
Leaves 3-nerved, subacute. 
Var. 6, tenuissimus. Fries. 
Prats MCCCCXX. : 
Reich. Ic. Fl. Germ. et Helv. Vol. VII, Tab. XXII. Fig. 39. 
Leaves very narrow, cuspidate, 3-nerved or 1-nerved, whole plant | 
smaller than var. «, and with the leaves more divaricate. 
In ponds and ditches. Rather common, and generally distributed, 
ranging from Cornwall, Dorset, Kent, and Sussex, northward to . 
Orkney. Frequent throughout Ireland. 
England, Scotland, Ireland. Perennial. Summer. 
Stems very slender, usually branched. Leaves $ to 2 inches long, 
rarely above ;!; inch broad, and in var. 6 searcely above y\; im 
Peduncles (exclusive of the spike) } to 1 inch long, much more slen 
than in any of the preceding species. Fruiting-spike } to } inch long, 
Nuts ;'; inch long. ¥ 
From P. mucronatus this differs in its more slender and uncom- 
pressed stem, its narrower leaves, with not more than three veins, and 
with their base much less narrowed, their apex less acuminate, 
much more slender peduncles, and the smaller, less compressed fruit, 
more convex on the lower side, and with the beak rather longer in pro- 
portion. Besides these characteristics, the mode of growth is different, 
the leaves are not so far apart, and have not fascicles of leaves or ve 
short branches in their axils, which is almost always the case in fF. 
