256 TETRANDRIA. TETRAGYNIA. Potamogeton, 
FL Ban. 1025— (E. Bot. 1822. E.)— Fuchs. 651 —Trag. 688— Mill. III.— 
Ger Em. 821. 1 —Pet. 5. 4— H. Ox. v. 29. row 1. 1. at p. 596— Ger. 675. 
1 —Park. 1254. l—Matth. 1137. 
( Stems much branched, extending several feet. Stipules large, concave, 
pale, membranous. Spikes one to two inches long, rising above the 
water from the base of the leaves, on fruit-stalks as large as the stem. 
Flowers sessile, numerous, olive green. Anthers yellow. Leaf-stalks for 
the most part longer than the leaves. E.) 
When growing in a place which is dried up in summer, it surprisingly 
changes its appearance, becoming upright, and resembling a small Plan - 
tago. Linn. Leaves alternate, except the upper pair, which are opposite ; 
lower ones spear-shaped, on long leaf-stalks ; upper ones oval, with 
shorter leaf-stalks. Stem about four inches high. 
Broad-leaved Pond-weed. (Irish: Builleasg na Auchun. Welsh: Byfr- 
llys llydan-ddail. Tafod y ci. E.) In ponds and slow rivers, common. 
P. July—Aug.* 
(P. heterophyl'lum. Leaves under the surface of the water membra¬ 
nous, strap-spear-shaped, sessile ; those floating coriaceous, ellipti¬ 
cal, having leaf-stalks; fruit-stalks thickest upwards. 
E. Bot. 1285— Fl. Ban. 222; hut wanting the floating leaves. 
A smaller plant than the preceding. Floating-leaves thinner, more pointed, 
seldom two inches long. Stems very much branched, wide-spreading, 
cylindrical, leafy on all sides. Leaves very entire, pale green, slightly 
striated. Sheath-scales within the leaves, oblong, bluntish. Floral- 
leaves broader than the sheath-scales, keeled, concave. Spike simple, 
greenish. Fl. Brit. 
Various-leaved Pond-weed. (Welsh: Byfr-llys amryddail. E.) P. 
heterophyllum , Schreb. HofFm. Willd. P. palustre. Teesd. Relh. In 
ditches and stagnant ponds. In ditches near Beverley, Yorkshire. Mr. 
Teesdale. Berrington Pool, Shropshire. Rev. Mr. Williams. At Old 
Buckenham, Norfolk. Mr. D. Turner. Near Forfar, Scotland. Mr. G. 
Don. Fl.Brit. Near Diss, Norfolk. Mr. Woodward. Burwell Fen, 
Cambridgeshire. Relhan. P. July—Sept. E.) 
(P. flu'itans. Lower leaves spear-shaped, tapering to a point, mem¬ 
branous : upper-leaves oval-spear-shaped, somewhat coriaceous, 
all the leaves having leaf-stalks. 
(Hook. Fl. Lond. 172. E.)— E.Bot. 1286—(Fl. Ban. 1450. E.) 
Nearly the whole plant grows under water; the uppermost leaves alone 
swimming on the surface, and bearing up the spikes. Stems floating, very 
* The leaves floating upon the surface of the water afford an agreeable shade to fish, 
and are the habitation and food of Phalxna Potamogeton. (The common Water-fly does 
not swim, in the usual manner, upon its belly, but on its bach; (and hence denominated 
JNotonecta ;) nor can we help admiring that fitness of this insect for its situation, as it feeds 
on the under side of plants which grow on the surface of the water, and has even a mouth 
peculiarly placed to enable it to take its food with greater convenience. E.) The roots are 
a favourite food of swans. Their love of this plant, so troublesome in still pieces of water, 
is such, that by harassing it in search of its succulent roots during winter, a pair of them 
have almost destroyed it in the whole extent of nearly five acres of water, which at times has 
been completely matted over with it. Mr. Stackhouse. (These aquatics, when collected in 
large quantities, are serviceable for manure. E.) 
