ELATINACEAE (WATERWORT FAMILY) 676 



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

 Low grounds, conmion. 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.; north w. 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 suhcordate 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. (11. 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 l-^-nerved, linear to linear-oblanceolate, rounded 

 at tip, narrowed to the sessile or subpetiolar base, 1-4 cm. long, 1-0 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 oi 



appressed. 



21. H. Dnimm6ndii (Grev. & Hook.) T. & G. Stem and the mostly alternate 

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

 \-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. Out. 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. virginicum L. (Marsh S.) Stoloniferous ; leaves closely sessile or 

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

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

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

 tone, 



I 24. H. petiolitum Walt. (Marsh S.) Taller, more branching ; Z^ayes «a;)<'7-- 

 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 floioers like those of the Chickweeds, but the pod 

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



1. Elatine. Flowers 2-l-merou8. Capsule globose. Glabrous, growing In or near water. 



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



