halokagejE. (water-milfoil family.) 175 



* Stamens 8 : petals deciduous; carpels even : leaves whorkd in threes or fours. 



1. M. spicAtum, L. Leaves all pinnately parted and capillary, except 

 ih&JUrral ones or bracts; these ovate, entire or toothed, and chiefly shorter than the 

 _/?owers, which thus form an interrupted spike. — Deep water: common. (Eu.) 



2. M. vertieiU^tum, L. Floral leaves much longer than the flowers, pec- 

 tinate-pinnatifld : otherwise nearly as No. 1. — Ponds, &c. northward. (Eu.) 



* * Stamens i : petals rather persistent : carpels I - 2-ridged and roughened on the 



back: leaves whorkd infljurs andflves, the lower with capillary divisions. 



3. M. heteroph^Uum, Michx. ^t^xaitaui; floral leaves ovate and lance- 

 olate, thick, crowded, sharply serrate, the lowest pinnatifid ; fruit obscurely rough- 

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



4. M. SCabr^tum, Michx. Stem rather slender ; lower leaves pinnately 

 parted with few capillary divisions ; floral leaves linear (rarely scattered), pectinate- 

 toothed or cut-serrate : carpels strongly 2-ridged and roughened on the back. — Shallow 

 ponds, from S. New England and Ohio southward. 



* * » Stamens 4 : petals rather persistent : carpets even on the back : leaves chiefly 



scattered, or wanting on the flowering stems. 



5. M. ambiguum, Nutt. Immersed leaves pinnately parted into about 10 

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

 linear and sparingly toothed or entire ; flowers mostly perfect ; fruit (minute) 

 smooth. — Var. 1. nAtans : stems floating, prolonged. Var. 2. capillIceum: 

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

 3. lim6sum : small, rooting in the mud ; leaves all linear, incised, toothed, or 

 entire. — Ponds and ditches, Massachusetts to New Jersey, Pennsylvania, and 

 southward, near the coast. 



6. M. ten^Uum, Bigelow. Flowering stems nearly leafless and scape-like, 

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

 small, entire ; flowers altei-nate, monoecious ; fruit smooth. — Borders of ponds, N. 

 New York, New England, and northward. 



2. PEOSERPINACA, L. Meemaid-weed. 



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

 mens 3. Stigmas 3, cylindrical. Fruit bony, 3-angled, 3-celled, 3-sceded, nut- 

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

 name, from proserpo, to creep), alternate leaves, and small flowers sessile in the 

 axils, solitary or 3-4 together, in summer. 



1 . P. pall!istris, L. Leaves lanceolate, sharply serrate, the lower pectinate 

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



2. P. peotin&cea, Lam. Leaves all pectinate, the divisions lincar-awl- 

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



9. HIPPURIS, L. Make's Tail. 



Flowers perfect or polygamous. Calyx entire. Petals none. Stamen one, 

 inserted on the edge of the calyx. Style single) thread-shaped, stigmatie down 

 one side, received in the groove between the lobes of the large anther. Fruit 



