50 
DIANDRIA. MONOGYNIA. Lemna. 
young fronds.) Covers ditches and stagnant waters with an entire 
floating m^ss of green. The flowers are seldom to be found where the 
plants are in the highest state of vegetation,, for scarcely have the ear¬ 
liest flowers disappeared, than the plants which produce them verge to¬ 
wards decay, and sink in a state of fructification to the bottom, where 
they perish, disseminating the seed, which becomes a young plant, and, 
as Valisneri has observed, rises early in the next spring to the surface. 
Fruit exactly resembling that of L. trisulca. FI. Lond. E.) 
Lesser Duck-weed. Greeds. (Welsh: Bwyd hwyaid. Irish: Gran 
Lagan. E.) In pools (common. Mr. Turner states that this and the 
preceding species flower regularly every year in June, in marshes at 
Bradwell in Suffolk. And generally near London. E.) A. June—Sept.* 
L. gib'ba. Leaves (fronds, E.) sessile, hemispherical beneath: roots 
solitary. 
{Hook. FI. Lond. 211— E. Bot. 1233. E.)— Mich. 11 . 1. 2. 3,* Lenticula — 
J. B. iii. 773. 3. 
(Distinguished from L. minor chiefly by the hemispherical, pale under-side 
of its frond , which is pellucid, apparently cellular, and reticulated; 
upper surface sometimes tinged with purple. The general character, 
mode of growth and fructification, resemble those of the other spe¬ 
cies. E.) 
Gibbous Duckweed. L. minor gihba \ 3 . Huds. Ditches and ponds (com¬ 
paratively rare. Ditches adjoining Rhyd Marsh, near Prestatyn, Flint¬ 
shire. Mr. Griffith. E.) Lower Bishop’s pool. North wick, near 
Worcester, and in a pool near the east side of Malvern Chase. Stokes. 
(Mill-pond, near St. Nicholas Church, and in a brook in Baly’s Lammas, 
Warwick. Perry. Lochend, Edinburgh. Greville. Found in fructification 
at Lewes by Mr. Borrer. E. Bot. E.) A. July—Aug. 
L. polyrrhi'za. Leaves (fronds, sessile, roundish-obovate, convex 
beneath: roots crowded, from one point. E.) 
{E .Bot. 2458. E .)—Ray 4. 2. at p. 150— VaiU. 20. 2—Mich. 11. 1 . Leu- 
ticularia — {Mag. Nat. Hist. v. i. p. 290. E.) 
(Twice or thrice as large as the preceding species. Fronds half an inch 
in length, and nearly as broad, faintly striated, green above, purple be¬ 
neath. E.) 
Greater Duck-weed. Ditches, common ; (but seldom, if ever, found in 
flower in England. A. May—Sept.t 
* (It has been observed that various kinds of mosses which grow on walls and house¬ 
tops, although dried by the heat of summer so as to become quite brittle and friable, re¬ 
cover their former verdure and vegetative power by the first showers of autumn. A 
fact analogous to this, referring to plants destined to grow in ponds which fail in dry 
seasons, affords a striking example of suspended animation and resuscitation, as com¬ 
municated by Mr. Gough of Kendal. Some plants of L. minor were collected from a 
pond in July, 1797, dried four or five hours in the sun, and preserved in a small box, to 
the end of March, 1800 ; they were then placed in a glass jar with water, and not only 
revived, but flowered in the following August. Month. Mag. 1801. E.) 
f (The Lemnee generally are considered, like the freshwater Confervce, to possess the 
property of purifying the unwholesome air in marshy places, absorbing this air during the 
day, and exhaling oxygen during the night. Hooker, E.) Ducks and geese are fond 
of all the species. 
