DIANDUIA. MONOGYNIA. Lemna. 
49 
LEM'NA. # (Bloss . none: Cal. of one leaf: Caps, one-celled ; 
a utricle. Hook. Plants minute, frondose. Grev. E.) 
L. trisul'ca. Leaves (or fronds. E.) on leaf-stalks, spear-shaped, 
proliferous. 
{Hook. FI. Lond. 119 —E.Bot. 926. E .)~~Mich. 11. 5—J.B. iii. 786. 1— 
Lob. Ic. ii. 36. l—Ger. Em. 830. 2—Park. 1216. 9—Ger. 681. 2. 
(A pale green, pellucid, smooth herb, floating in fresh water, near or upon 
the surface, the flowers spring from a lateral chink, whose margin forms 
the calyx. The barren Jlowers , (as they were wont to be considered, 
E.) have two ascending white smooth stamens, each with a two-lobed 
yellow anther. In some an ovate superior germen stands between the 
stamens, bearing a simple style, with a cloven stigma. E. Bot. Few 
Botanists have seen the fructification of this singular plant, either at 
home or abroad; in the month of June, near Yarmouth, Mr. D. Turner 
was so fortunate as to discover it in perfection, and Mr. Graves since 
several times near London. E.) 
(From the centre of the under side of the fronds descend fibres or radicles, 
which never reach to strike into the earth, but are terminated by a dis¬ 
tinct sheath, like the calyptra of a moss. Their common mode of in¬ 
crease is by gemmae, which are produced in marginal clefts near the base 
of the leaf, and there expand into perfect plants, and these again bear 
other fronds. The structure of the flowers is no less curious: they are 
likewise produced singly in a lateral cleft; a solitary pistil is mostly ac¬ 
companied by two anthers, and surrounded by a membranous urceolate 
covering, usually considered the calyx or corolla ; but Mr. Brown is satis¬ 
fied that this genus belongs to the natural order of Aroideae , and that 
this plant is not truly diandrous, with the stamens placed on each side 
the germen, and not advancing progressively; on the contrary, they are 
placed both on one side, both beneath the germen, and are not seen both 
in perfection at the same period. The receptacle is to be looked upon 
as a spadix, and the pistil and two anthers as so many distinct naked 
flowers which it produces; the whole being surrounded by a spatha (the 
calyx or corolla of authors). The singular economy of these minute ve¬ 
getables is beautifully illustrated by the plates of FI. Loud-, Professor 
Hooker having had opportunities of analyzing both this and the fol¬ 
lowing species in all stages of fructification. E.) 
Ivy-leaved Duck-meat or Duck-weed. Ditches and stagnant waters, 
common; (but rarely observed in flower. E.) A. June—Sep.f 
L. mi'nor. Leaves (or fronds. E.) sessile, fiattish on both sides: roots 
solitary. 
{Hook. FI. Lond. 120— E. Bot. 1095. E.)— Ray. 4. 1. at p. 150— Mich. 11. 
3, Lenticularia — Vaill. 20. 3— Blackw. 380— Gars. 336— Trag. 690— 
Bod. 587. 1— Lob. Obs. 64<8. 1; and Ic. ii. 49. 1— Ger. Em. 829. 1— 
Park. 1262. l—Ger. 680—Matth. 1115—,/. B. iii. 773. 2. 
{Fronds about a line and a half long, slightly convex beneath, rather thick, 
succulent, and firm in texture. Increasing prodigiously by gemmae , (the 
* (Supposed of Greek origin, but of doubtful meaning. E.) 
t (The individuals float upon the surface of the water, collected together in great 
masses, affording harbour for various aquatic insects, and food for ducks and other water 
fowl. E.) 1 
