HALORAGE.E. (WATER-MILFOIL FAMILY.) 181 



1. MYRIOPHYLLUM, Vaill. WATER-MILFOIL. 



Flowers monoecious or polygamous Calyx of the sterile flowers 4-parted, 

 of the fertile 4-toothed. Petals 4, or none. Stamens 4-8. Fruit nut-like, 4- 

 celled, deeply 4-lobed ; stigmas 4, recurved. Perennial aquatics. Leaves 

 crowded, often whorled ; those under water piniiately parted into capillary 

 divisions. Flowers sessile in the axils of the upper leaves, usually above water 

 in summer ; the uppermost stamiuate. (Name from /uvptos, a thousand, and 

 0jA.Aoc, a leaf, i. e., Milfoil.) 



* Stamens 8 ; petals deciduous ; carpels even ; /eaves ivhorled in threes or fours. 



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

 the floral ones or bracts ; these ovate, entire or toothed, and chiefly shorter than 

 the flowers, which thus form an interrupted spike. Deep water, Newf. to N. 

 Eng. and N. Y., west to Minn., Ark., and the Pacific. (En.) 



2. M. verticillatum, L. Floral leaves muck longer than the flowers, pec- 

 tinate-pinnatffid ; otherwise nearly as n. 1. Ponds, etc., common. (Eu.) 



* * Stamens 4; petals rather persistent ; carpels l-2-ridged and roughened on 

 the back ; leaves whorled in fours and jives, the lower with capillary divisions. 



3. M. heterophyllum, Michx. Stem stout ; floral tea ves ovate and lance- 

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

 ened. Lakes and rivers, Ont. and N. Y. to Fla., west to Minn, and Tex. 



4. M. scabratum, Michx. Stem rather slender ; lower leaves pinnately 

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

 tinate-toothed or cut-serrate ; carpels strongly 2-ridged and roughened on the back. 

 Shallow ponds, S. New Eng. to S. C., west to Mo. and La. 



* * * Stamens 4; petals rather persistent; carpels 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. Ponds and ditches, Mass, to N. J. and Penn. ; also in Ind. Var. 

 CAPILLACEUM, Torr. & Gray, has stems floating, long and very slender, and 

 leaves all immersed and capillary. Var. Liiidsusi, Torr., is small, rooting in 

 the mud, with leaves all linear, incised, toothed, or entire. 



6. M. tenellum, Bigelow. Flom-ring stems nearly 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, 

 Newf. to N. Eng., west to Mich. 



2. PROSERPINACA, L. MERMAID-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-seeded, nut- 

 like. Low, perennial herbs, with the stems creeping at base, alternate leaves, 

 and small flowers sessile in the axils, solitary or 3-4 together, in summer. 

 (Name applied by Pliny to a Polygonum, meaning pertaining to Proserpine.) 



1. P. pallistris, L. Leaves lanceolate, sharply serrate, the lower pectinate 

 when under water ; fruit sharply angled. Wet swamps, N. Eng. to Fla.. west 

 to Minn, and Tex. 



