ELATINACEAE (WATERWOIIT FAiMILV) 576 



Janceolate, acute ; po(Zs 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, 8-9 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 O.; 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-tierved, linear to linear-oblanceolate, rounded 

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

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

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

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

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



-1- -1- Stems fastigiately branched; leaves linear or bract-like, ascending or 



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

 bushy branches rigid, erect, 1.6-8 dm. high ; leaves linear-subulate, nearly erect, 

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

 branches, short-^ediceled ; pods ovoid, not longer than the calyx. — Dry soil, 

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



22. H. gentianoides (L.) BSP. (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 h.; B. 

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

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



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

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

 E LODES Man. ed. 6, not Adans. 



23. H. virginicum L. (Marsh S.) Stoloniferous ; 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. petiolitum 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 between the opposite dot- 

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

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



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

 8. Bergia. Flowers S-ruerous. Capsule ovoid. Plant pubescent, terrestrial. 



