ELATINACEAE (WATERWORT FAMILY) 575 



lanceolate, acute; pods 2.5-3.5 mm. long, short-ellipsoid, rounded at apex. 

 Low grounds, common. July, Aug. 



18. H. gymndnthum Engelm. & Gray. Almost simple, with strict stem and 

 branches, 3-9 dm. high ; leaves clasping, heart-shaped, acute or obtuse ; cyme 

 naked, the floral leaves reduced to small awl-shaped bracts ; pods slender-coni- 

 cal, pointed, 4-5 mm. long, slightly exceeding the lance-acuminate sepals. 

 Wet sandy barrens, N. J. and e. Pa. to Fla. and Tex.; northw. in Miss, basin to 

 Mo., 111., Ind., and (.).; reported also from Minn. 



19. H. majus (Gray) Britton. Annual, or perennial by short leafy offshoots ; 

 stems solitary or tufted, erect, rather stout, 1-7 dm. high ; leaves chiefly 5-7- 

 nerved at the rounded or subcordate sessile or clasping base, lanceolate, the upper 

 acute or bluntish, 1.5-4.5 cm. long, 3.5-13 mm. broad ; cymes essentially naked, 

 the bracts slender ; sepals lance-attenuate, 5-7 mm. long, nearly equaling the 

 conic-ellipsoid bluntish pod. (H. canadense, var. Gray.) Wet or dry open 

 soil, e. Que. to Man., s. to L. I., N. J., Pa., 111., la., and S. Dak.; also e. Wash. 

 July, Aug. 



20. H. canadense L. Annual, or perennial by short leafy offshoots ; stems 

 slender, 1-4 dm. high ; leaves 1-3-nerved, linear to linear-oblanceolate, rounded 

 at tip, narrowed to the sessile or subpetiolar base, 1-4 cm. long, 1-6 mm. broad ; 

 cymes naked except for the linear-setaceous bracts; sepals linear-lanceolate, 

 blunt or acutish, 2.5-5 mm. long, much shorter than the slender-conical red or 

 purplish pod. Wet or dry, chiefly exsiccated places, Nfd. to Man., s. to Ga., 

 Ky., Wise., and Minn. July-Sept. 



- *- Stems fastigiately branched; leaves linear or bract-like, ascending or 



appressed. 



21. H. Drumm6ndii (Grev. & Hook.) T. & G. Stem and the mostly alternate 

 bushy branches rigid, erect, 1.5-8 dm. high ; leaves linear-subulate, nearly erect, 

 l-nerved, 6-20 mm. long ; flowers scattered along the upper part of the leafy 

 branches, short-pediceled ; pods ovoid, not longer than the calyx. Dry soil, 

 Ashtabula Co., O. (Louth), 111., la., Kan., and southw. 



22. H. gentianoides (L.) B S P. (ORANGE GRASS, PINEWEED.) Stem and 

 bushy branches thread-like, wiry, 1-3 dm. high ; leaves minute awl-shaped scales, 

 appressed; flowers minute, mostly sessile and scattered along the erect branches; 

 pods ovoid-lanceolate, acute, much longer than the calyx. (Sarothra L.; H. 

 nudicaule Walt.) Sandy or rocky soil, Me. to Fla. and Tex., chiefly e. of the 

 Alleghenies ; and from s. w. Ont. to 111., and southw. 



6. EL6DEA (Juss.) Choisy. Petals imbricated in bud, flesh-colored or pur- 

 plish. Stamens mostly 9, in 3 bundles. Styles 3, distinct. ELODEA Juss.; 

 ELODES Man. ed. 6, not Adans. 



23. H. virgfnicum L. (MARSH S.) Stoloniferons ; leaves closely sessile or 

 clasping by a broad base, oblong or ovate, very obtuse ; filaments united below 

 the middle. (Triadenum Raf.; Elodea campanulata Pursh.) Common in 

 swamps. July, Aug. The entire plant frequently has a pink or crimson 

 tone. 



24. H. petiolHtum Walt. (MARSH S.) Taller, more branching ; leaves taper- 

 ing into a short petiole, oblong ; filaments united beyond the middle. (Triade- 

 num Britton.) Cypress swamps, etc., N. J. to Mo., and southw. 



ELATINACEAE (WATERWORT FAMILY) 



Little marsh annuals, with membranaceous stipules beticeen the opposite dot- 

 less leaves, minute axillary flowers like those of the Chickweeds, but the pod 

 2-5-celled, and the seeds as in St. John's-wort. 



1. Elatine. Flowers 2-4-merous. Capsule globose. Glabrous, growing in or near water. 



2. Bergia. Flowers 5-merous. Capsule ovoid. Plant pubescent, terrestrial. 



