ELATINACEAE (WATRinVORT FAMILY) 576 



.ancedate, acute ; pods 2.5-8.5 mm. long. s^liort-eUipsoid., rounded at apex. — 

 Low grounds, coniinon. July, Aug. 



18. H. gymnanthum Eiigeliii. & 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. — 

 AVet 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. ma jus (Gray) Britton. Annual, or perennial by short leafy offshoots ; 

 stems solitary or tufted, erect, rather stout, 1-7 dm. high ; leaves chiefly u-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-atlenuate, 5-7 mm. long, nearly equaling the 

 conic-ellipsoid bluntish j)ofZ. {H. canadense, var. Gray.) — Wtt 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 ; leav(-s \^^-nerved, linear to lincar-oblanceolate, rotinded 

 at tip, narrovjed 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, Xfd. to Man., s. to Ga., 

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



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

 ^ appressed. 



21. H. Dnimm6ndii (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 ; floicers 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 south w. 



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 ; 

 podti ovoid-lanceolate, acute, much longer than the calyx. {Sarothra L. ; H. 

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

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



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

 plish. Stamens mostly 9, in o 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 ; filaments united below 

 the middle. {Triadenum Raf.; Elodea campanulata Pursli.) — Common in 

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

 tone. 



24. H. petiolatum 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 floioers like those of the Chickweeds, but the pod 

 2-6-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-iTierous. Capsule ovoid. Plant pubescent, terrestrial. 



