HALOUAGE^E. (WATEK-JIII.FOIL FAMILY.) 175 



• Stdtnetis 8: jntuls (hcidiioiis: carpels even: leaves irlwilfd in llireei or fours. 



1. M. spiCcltum, L. Leaves uU piiinately parttd ami capillary, except 

 ilnijlural outs or hracls ; these ovule, entire or tuvthul, and diiejlij slioiler than the 

 Jiuwers, wliiiU tluis lonii an inlerrupted sijike. — Deep water: eoiuiuoti. (Vm.) 



2. M. Verticillatum, -L. Flund kaces iiiHcli louijer titan Iht- Jluwers, jiec- 

 tinate-pinnulijid : otherwise nearly as ^'o. 1. — Tonds, &.Q. northward. (Eu.) 



* * Stamens 4: pettds rather persistent: carpels \-2-ridijed and ronijht ned on tlie 



lath: If-aces wliorleti in fours and fives, the lower with capdlanj divisions. 



3. M. heterophyiium, Miehx. Sti:m stont ; Jloral leavis ovate and lance- 

 oltite, thick, crowded, sharjily serrate, the lowest pinnatifid ; fndt ohsrure/y rough- 

 ened. — Lakes and rivers, from N. New York westward and southward. 



4. M. scabr^tum, Miehx. Stem rather slender; lower leaves pinnatcly 

 parted with tew capillary divisions ; Jlorul leaves linear {rurcly scattei'cd), jMctinute- 

 tuothed or cut-serrate: carpels strom/ly 2-rid(/ed and roughened on the hack. — Shallow 

 ponds, from S. New England and Ohio sonthw^ard. 



* * * Stamens \: petals rather persistent : carpels even on the hack : leaves chiefly 



sctittered, or waiitinrj on the flowering stems. 



5. M. ambigUUm, Nutt. Immersed leaves immatthj parted into about 10 

 very delicate capillary divisions; the emerging ones pectinate, or llf tipper floral 

 linear and s])arin};iy toothed or entire; flowers viostli/ perfect; fruit (minute) 

 smooth. — Var. 1. n.Vtaxs ; stems floatinp;, prolonjjed. Var. 2. cai'ili-Xceim: 

 stems floating, long and very slender ; leaves all immersed and capillary. Var. 

 3. mm6sum : small, rooting in the mud ; leaves all linear, incised, toothed, or 

 entire. — Ponds and ditclies, Massachusetts to New Jersey, Pennsylvanin, and 

 southward, near the coast. 



6. M. teil611um, Bigelow. Flowering stems nenrlg leafless and scape-like, 

 (3'- 10' high), erect, simple; the sterile shoots creeping and tufted; bracts 

 small, entire ; flowers alternate, monoecious ; fruit smooth. — Borders of ponds, N. 

 New York, New England, and northward. 



2. PROSERPINACA, L. Meumaid-weed. 



Flowers perfect. Calyx-tube 3-sided, the limb 3-parted. Petals none. Sta- 

 miMis ;3. Stigmas 3, cylindrical. Fruit bony, 3-angled, 3-celled, 3-seeded, nut- 

 like. — Low, perennial herbs, with the stems creeping at the base (whence the 

 name, Irom proserpo, to creep), alternate leaves, and small Howers sessile in the 

 axils, .'olitary or 3-4 together, in sunnuer. 



1. P. pallistriS, L. /x«ics lanceolate, sharply senate, the lower pectinate 

 when under water; fruit sharply angled. — Wet swamps: not rare. 



2. P. pectin^cea, Lam. Leaves all pectinate, the divisions liuear-awl- 

 shaped ; fruit rather obtusely angled. — Sandy swamps, near the coast. 



9. HIPPURIS, L. .Mahl's Tail. 



Flowers jK-rfect or ])o!yganious. Calyx entire. IVtals none. Stamen one, 

 inserted on the edge of the calyx. Stylo single, thrend-shaj;ed, stigniatie down 

 one side, received in the groove Ix'twceu the lobes of the largo anther. Frui' 



