Order 136.— HYDROCH ARID ACE^E. 679 



Order CXXXVI. HYDRO CH ARID ACE^E. Frogbits. 



Aquatic herbs with parallel-veined leaves and diclinous fls. on a slender-stalked 



*padix. Perianth regular, 3 to 6-parted, the inner segments petaloid. Stamens 3 



to 12. Ovary adherent to the perianth, 1 to 9-celled, with 3. 6 or 9 large stigmas. 



Fruit dry or succulent, many-seeded, indehisent. Seeds without albumen. 



Genera 12, upecien 20, native of fresh water in Europe, N. America, E. Indies and N. Holland. 

 They appear to possess no active properties. 



i. LIMNO'BIUM, Richard. Frogs-bit. (Gr. Xipvr], a lake, j3io$, 

 life.) Flowers monoecious, arising from subsessile spathes ; $ spathe. 

 1 -leaved, about 3-flowered, calyx 3-sepaled, corolla 3-petaled, petals ob- 

 long-linear ; stamens 6 to 12, monadelphous ; $ spathe 2-leaved, 1- 

 flowered ; calyx and corolla as in the t ; stamens 6, subulate rudiments ; 

 ovary 6 or 9-celled, becoming a co-seeded berry. — 2£ Herb acaulescent, 

 in stagnant waters, multiplying by stolons, and with floating lvs. Fls. 

 showy, white, the £ on long stalks. 



I». Spongia Rich. — In Braddock's Bay, L. Ontario (Sartwell) ; scarce at the north, 

 common in the south, E. Ky. ! to Ga. (Feay) and La. (Hale). Lvs on long pe- 

 tioles, roundish, obtuse or broadly acute, often cordate, 1' to 18" diam. Ped. of 

 the sterile fls. slender, about 3' long, of the fertile, thick, about 1' long, both 

 kinds either together on the same stalk or on different stalks which are connected 

 by the stolons (Dr. Feay). The leaves beneath are purplish and spongy with large 

 cells. Jl., Aug. (Hydrocharis, Bosc H. cordifoiia Nutt.) 



2. ANACH'ARIS, Richard. Ditch Moss. (Gr. dv, an indefinite par- 

 ticle, &xapiS, uncomely.) Flowers polygamous, solitary, from a tubular, 

 bifid, axillary spathe ; perianth 6-parted, colored ; $ minute, with 9 

 oval, nearly sessile anthers ; ? perianth excessively produced into a 

 filiform tube above the ovary, limb 6-parted, stamens 3 to 6, often abor- 

 tive ; style capillary ; adherent to the tube of the perianth ; stigmas 3, 

 large; fruit few-seeded. 71 Small aquatic herbs, with submersed pellu- 

 cid opposite or verticillate lvs. 



A. Canadensis Planchon. Lvs. verticillate in 3s and 4s, lanceolate, oblong or 

 linear surrulate ; stig. 2-lobed. — Resembling a coarse moss, in still waters and 

 bogs. St. filiform, diffusely dichotomous, very leafy. Lvs. 3 to 6" by (less than) 

 1", thin and diaphanous, sessile, obtuse. Fls. minute, of a dingy white, the slen- 

 der, hair-like tube 2 to 10' long, according to the depth of the waters. Stigmas 

 recurved between the segments, crested with glandular hairs. Aug. (TJdora, 

 Nutt.) 



3. VALLISNE'RIA, Michelc. Eel-grass. (In honor of Anthony 



Vallisner, a French botanist.) Flowers $ ? ; spathe ovate, 2 to 4- 

 parted. <$ Spadix covered with minute flowers, enclosed in a 3-parted 

 spathe ; corolla 0. $ Spathe bifid, 1 -flowered ; perianth elongated ; 

 sepals linear ; stigmas 3, ovate, bifid ; fruit elongated, cylindrical, many- 

 seeded. — 21 Submersed. Lvs. all radical, grass-like. Scape spiral, 

 very long. 



V. spiralis L. Lvs. linear, obtuse, serrulate at the end, tapering at the base, 

 floating. — A curious plant, in slow moving or stagnant waters, U. S. Leaves 

 linear, 1 — 2f long, about \' wide, the edges thinner than the middle. Scapes 

 several, of the sterile plants short, of the fertile plants very tortuous, 2 — 4f long 

 when extended, thread-like, thickened at the top, bearing each a single, white 

 flower at. or near the surface. Sepals and petals crowning the (1') long, narrow, 

 incurved ovary, which, is half concealed in the spathe. Jl., Aug. (V. Amer- 

 icana Mx.) 



