Herbs minute, stemless, floating free upon the water, and consisting of a leaf-like frond, or a tuft of leaves, with one or more fibrous roots. Flowers bursting from the substance of the frond, or axillary, inclosed in a spathe, the sterile consisting of

1 or 2 stamens, the fertile of a 1-celled ovary. Fruit a utricle, with 1 or more seeds.

Embryo straight, in fleshy albumen. Fig. G02.

Genera 4, species 20, little aquatics, widely diffused. They are regarded as reduced aroids, and among the simplest of Phenogamous plants.

. 1. LEM'NA, L. Duck-meat. (Perhaps altered fromOrder CXXXII Lemnaceae Duckmeats 1894 a scale.) Sterile and fertile flowers in the same spathe, the former 2 collateral stamens, the latter a simple, carinate ovary, with a style and stigma. - Order CXXXII Lemnaceae Duckmeats 1895 Herbs, consisting of a frond (stem and leaf confounded), sending down from the under surface roots which hang loosely in the water, and producing from the margins the spathaceous flowers. (The following sections are regarded as genera by Schleiden.)

§ LEMNA, Schleiden. Fils. filiform. Ovule solitary. Frond with a single root...........

Nos. 1 - 3

§ TELMATOPHACE, Schl. Fils. dilated in the middle. Ovs. 2 to 7 Fronds 1-rooted....

No. 4

§ SPIRODELA, Schl. Fils. narrowed below. Ovules 2. Frond many-rooted...........

No. 5

1 L. trisulca L. Ivy-leaved Duck-meat. Fronds elliptic-lanceolate, thin, serrate at one extremity and caudate at the other; roots solitary. - Floating in ponds and pools of clear water. Fronds nearly 1/2' in length, diaphanous, with a tail-like appendage at base, obtuse at apex, the new ones issuing in a cruciate manner from lateral fissures in the margin of the old. Root a solitary fiber, ending in a sheath. Flowers very minute. Utricle sitting on the upper surface of the frond. June - Sept.

2 L. minor L. Fronds thickish, roundish or obovate, several conjoined; root solitary. - This little floating plant occurs in dense patches on the surface of stagnant waters. The leavrs, properly fronds, adhere 2 - 3 together, 2" in length, rather thick, and convex below. Root undivided, sheathed at the end. Flowers minute from a cleft in the margin of the fronds, near the base. Jn. - Sept

3 L. perpusilla Torr. Smallest Duck-meat. Fronds obovate, thin; rt. solitary; seed erect. - Ponds on Staten Island. Fronds 1" or more long, grouped or single, bright green. Stamens with filiform filaments, maturing in succession. Ovary obliquely acuminate, with a short style. Sd. striate, erect in the ovary. Aug. (Torrey).

4 L. gibba L. Fronds obovate, hemispherical beneath, nearly plain above; root solitary. - Floating on the surface of stagnant waters, N. York. Fronds about a line in length, pellucid and reticulated beneath. Filaments recurved as in the other species. Fruit roundish, indehiscent, 1 to 7-seeded. Jn., Jl.

5 L. polyrhiza L. Fronds broad-ovate, a little convex beneath, rts. numerous. - Floating in stagnant waters. Fronds resembling flax-seed, but larger (2 to 4" long), scattered on the surface of the water, of a firm, but succulent texture, becoming purplish. Rts. in thick bundles of 8 to 10 black fibers from the under surface of the fronds. All these species are eaten by ducks and other aquatic birds. Jn. - Sept.

2. PIS'TIA, L. (Gr.Order CXXXII Lemnaceae Duckmeats 1896 drinking.) Spathe tubular at base, connate with the spadix, limb open, ligulate, cucullate above;. Order CXXXII Lemnaceae Duckmeats 1897 anthers 3 to 8, adnate to the thick summit of the spadix, subglobous, opening transversely; Order CXXXII Lemnaceae Duckmeats 1898 ovary 1, at the base of the spadix, 1-celled, ∞-ovuled, becoming a berry in fruit. - Floating herbs, consisting of rosulate tufts of little, veined, entire lvs., sending out filiform stolons. Spadix axillary, on a short scape.

P. Stratiotes L. Lvs. roundish-obcordate, margin undulate, veins lamelliform, confluent into a truncate area at base. In the var. spathulata (P. spathulata Mx.) the leaves are rather obovate than obcordate, and abruptly contracted into a short petiole. -Order CXXXII Lemnaceae Duckmeats 1899 S. Car. to Fla and La. (Curtis), in stagnant waters. Spathe white. May.