Fam. 96. Haloragaceae R. Br. Water-milfoil Family 



Aquatic or paludal plants with the inconspicuous symmetrical perfect or uni- 

 sexual flowers sessile in the axils of leaves or bracts; calyx tube (hypanthium) 

 adherent to the ovary that consists of 3 (or 4) united carpels; styles or sessile 

 stigmas distinct; limb of the calyx obsolete or very short in perfect or pistillate 

 flowers; petals small or none; stamens 1 to 8; fruit indehiscent, 3- or 4-celled, with 

 a single anatropous seed suspended from the summit of each cell. 



About 120 species in 6 genera, cosmopolitan. The name is sometimes misspelled 

 "Haloragidaceae." 



1. Flower parts in threes; leaves alternate, the emersed ones amply foliaceous 

 1. Proserpinaca 



1. Flower parts in fours; leaves whorled or rarely partly opposite or alternate, 

 the emersed ones much-reduced and mostly bractlike (sometimes 

 enlarged in M. heterophyllum) 2. Myriophyllum 



1. Proserpinaca L. Mermaid-weed 



Low herbaceous perennials with simple or sparsely branched stems that are 

 creeping and rooting at the rhizomatous base; leaves alternate, pinnately dissected 

 or the upper ones lanceolate and serrate, those on the same plant uniform or of 

 both extreme types and intermediate forms; flowers sessile and solitary in the leaf 

 axils, perfect; calyx 3-parted; corolla wanting; stamens 3; pistil 3-angled, with 3 

 stigmas; fruit nutlike, 3-angled, 3-celled, 3-seeded. 



Several species in North America. 



The fruits of these plants are eaten by waterfowl, especially ducks, and sparingly 

 so by muskrats. 



1. Upper leaves lanceolate, serrate 1. P. palustris. 



1. Upper leaves like the lower ones, pinnately divided 2. P. pectinata. 



1. Proserpinaca palustris L. Fig. 565. 



Plant repent and rooting along the stems at base; stems ascending or suberect, 

 occasionally trailing up into shrubs, to 1 m. or more long, the base submersed, the 

 summit becoming emersed; submersed leaves rufescent, sessile, finely pinnatified, to 

 6 cm. long, with 8 to 14 linear-filiform divisions on each side, the divisions to 3 cm. 

 long, commonly bearing minute black axillary spicules, the median portion linear and 

 about 1 mm. wide; amphibious leaves petioled, pinnatisect, to 7 cm. long, lanceo- 

 late, with the lanceolate middle portion to 1 cm. broad; emersed leaves lanceolate 

 to oblanceolate, to 85 mm. long and 15 mm. wide, serrate; flowers in leaf axils of 

 only the serrate leaves, solitary or in clusters of 2 to 5, subtended by minute lanceo- 

 late serrate bracts; calyx tube 3-angled, its ovate to deltoid lobes obtuse to acute; 

 petals rudimentary; fruit trigonous-urceolate or pyramidal, 2.5-6 mm. broad. 



In shallow water, about springs, in ditches and along shores of streams and lakes 

 in s.e. Okla. (Pushmataha Co.) and e. Tex., spring-summer; from e. Can., s. to 

 Ga. and Tex. 



Our plant belongs to var. amhlyogona Fern., characterized by having the angles 

 of the fruits rounded or nearly obsolete, or to var. creba Fern. & Grisc, with 

 angles of the fruit subacute. 



2. Proserpinaca pectinata Lam. Fig. 565. 



Stem very slender, repent, with an ascending rufescent summit to 3 dm. high; 

 leaves all deeply pinnatifid, ovate-elliptic in outline, to 25 mm. long, with a linear 

 median portion about 1 mm. wide and 4 to 9 slender rather firm divisions (to 7.5 

 mm. long) on each side, sometimes bearing minute black spicules; flowers solitary 

 or rarely in twos or threes in the middle and upper leaf axils; calyx lobes acuminate; 



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