20 H. ellipticum Hook. Herb smooth; st. quadrangular, simple; lvs. elliptical, obtuse, somewhat clasping, pellucid-punctate; cyme pedunculate; sep. unequal; sty. united to near the summit, as long as the ovary.- Low grounds Can. to Penn. St. 8 - 16' high, slender, colored at base. Lvs. 8 - 13" by 2 - 4", somewhat erect, about as long as the internodes. Cymes of about a dozen flowers, generally 1 or 2' above the highest pair of leaves. Central fls. subsessile. Petals acutish, orange-yellow, 2 - 3" long; sep. shorter. Stig. minute. Jl.
21 H. graveolens Buckley. St. terete, smooth, nearly simple; lvs. oblong-ovate, clasping, punctate beneath; cymes terminal and axillary; sep. and pet. narrow; fil. ∞; styles 3. - High Mts., N. Car. (Buckley). Plant with a strong odor. Stem 2 - 3f high. Lvs. 2' long, half as wide. Fls. largo and numerous. Jl. - Aug.
22 H. pilosum Walt. Herb rough-downy; st. simple, terete, virgate; lvs. ovate-lanceolate, oppressed, clasping, acute; cyme few-flowered; sty. distinct, as long as the ovary.- Wet pine barrens, S. Car. to Fla. and La., common. Lvs. 4 - 8" long, 1/2 as wide, very acute. St. 1 - 3f high, quite simple to near the top, clothed with a rough coat of hairs. Fls. 5 - 6" diam., mostly alternate on the branches of the cyme. Jn. - Sept.
23 H. mutilum L. Dwarf St. John's Wort. St. quadrangular, branched; lvs. obtuse, ovate-oblong, clasping, 5-veined, minutely punctate; cymes leafy; pet. shorter than the sep.; sta. 6 - 12. - Damp sandy soils, Can. to Ga., W. to Ind. St 3 - 6 - 9' high. Lvs. closely sessile, apparently connate, 4 - 8" by 2 - 5", outer veins obscure. Fls. minute, orange-colored. Jl., Aug.
24 H. Canadense L. St. quadrangular, branched; lvs. linear, attenuated to the base, with pellucid and also with black dots, rather obtuse; pet shorter than the lanceolate, acute sep.; sta. 5 - 10. - Wet sandy soils, Can. to Ga. St. 6 - 12' high, slightly 4-winged. Lower branches opposite, upper pair forked. Lvs. 8 - 12" by 1/2 - 1 or 2 , sometimes linear-lanceolate, radical ones obovate, short. Fls. small, orange-colored. Ova. longer than the styles. Caps. red, very acute, twice as long as the sepals. Jn. - Aug.
25 H. Sarothra Mx. St. and branches filiform, quadrangular; lvs. very minute, subulate; fls. sessile; sta. 5 - 10. - St. 4 - 8 - 12' high, branched above into numerous, very slender, upright, parallel branches apparently leafless, from the minuteness of the leaves. Fls. very small, yellow, succeeded by a conical brown capsule which is twice the length of the sepals. Jl., Aug.
.26 H. Drummondii Torr. & Gr. Branches alternate, square above; lvs. linear, very narrow, acute, longer than the internodes; fls. pedicellate; sta. 10 - 20; sep. lanceolate, shorter than the petals, but longer than the ovoid capsule.- Near St. Louis, to Ga. and La. Plant more robust than the last, 10 - 20' high, very branching. Lvs. 1/2' long. Fls. about 4" diam.
3. ELODEA, A dams. (Gr. έλώδης, marshy; from the habitat of the plants.) Sepals 5, equal, somewhat united at base; petals 5, deciduous, equilateral; stamens 9 (rarely more), triadelphous, the parcels alternating with 3 hypogynous glands; styles 3, distinct; capsule 3-celled.-
Herbs with pellucid-punctate lvs., the axils leafless. Fls. dull orange-purple.
1 33. Virginica Nutt. St. erect, somewhat compressed, branching; lvs. oblong amplexicaul; sta. united below the middle, with 3 in each set. - Swamps and ditches. U. S. and Can. Whole plant usually of a purplish hue, 9 - 20' high Lvs. 1 1/2 - 2 1/2' long, 1/2 as wide, upper ones lanceolate, lower oblong-ovate, all very obtuse, glaucous beneath. Fls. 5" diam., terminal and axillary. Pet. about twice longer than the calyx. Glands ovoid, orange-colored. Caps. ovoid-oblong, acutish. Jl. - Sept.
2 E. petiolata Ph. Lvs. oblong, narrowed at base into a petiole; fls. mostly in 3s, axillary, nearly sessile; filaments united above the middle; caps. oblong, much longer than the sepals. - Swamps S. States, N. to N. J. St. about 2f high. Lvs. 1 - 3' long, rounded-obtuse, with a short but distinct petiole. Fls. smaller than in the last. Aug., Sept.