[+][+] Styles 3; pod completely 3-celled.
3. H. prolíficum, L. (Shrubby St. John's-wort.) Branchlets 2-edged; leaves narrowly oblong (1–2´ long), mostly obtuse, narrowed at the base; flowers numerous, in single or compound clusters; pods lanceolate to ovate, 4–6´´ long.—N. J. to Mich., Minn., and southward. July–Sept.—Varies greatly in size, etc.
4. H. densiflòrum, Pursh. Exceedingly branched above, 1–6° high, the branches slender and crowded with smaller leaves; flowers smaller (½–{2/3}´ in diameter) and more numerous, in crowded compound cymes; pod 2–3´´ long. (H. prolificum, var. densiflorum, Gray.)—Pine barrens of N. J. to glades of Ky., Ark., and southward.
[*][*] Perennial herbs or a little woody at the base.
[+] Pod incompletely 3–4-celled.
5. H. galioìdes, Lam. Slender, branching, woody below; leaves linear-oblanceolate, narrowed downward, ½–3´ long, mostly acute; flowers small in terminal and axillary cymes; sepals very narrow, 1½–3´´ long; pod as long, ovate.—Del. to Ga. and E. Tenn.
6. H. adpréssum, Barton. Stem simple, herbaceous, from a slightly woody creeping base (1–2° high), obscurely 4-angled below and 2-edged above; leaves ascending, lanceolate or linear-oblong, often acute, thin; cyme terminal, leafy at the base, few-flowered; sepals linear-lanceolate, pods ovoid-oblong.—Moist places, Nantucket and R. I. to Penn., and southwestward. July–Aug.—Leaves 1½´ long. Petals bright yellow, 3–5´´ long.
[+][+] Pod 1-celled with 3 parietal placentæ.
7. H. dolabrifórme, Vent. Stems branched from the decumbent base, woody below (6–20´ high), terete; leaves linear-lanceolate, widely spreading, veinless; cyme leafy, few-flowered; sepals oblong or ovate-lanceolate, about the length of the very oblique petals (5–6´´ long); pods ovate-conical, pointed, the walls very thick and hard.—Dry hills and rocks, barrens of Ky. and Tenn. June–Aug.
8. H. cistifòlium, Lam.! Stems mostly simple, herbaceous, with a somewhat woody base, angled with 4 very narrow salient lines (1–2° high); leaves narrowly oblong to nearly linear (1–3´ long), sessile with a somewhat clasping base; the cyme naked, compound, usually many-flowered; sepals ovate; pods depressed-globular or ovoid-conical; seeds large, oblong, very rough-pitted. (H. sphærocarpon, Michx.)—Rocky river-banks, S. W. Ohio, to Iowa and southward. July–Sept.—Flowers small.
9. H. ellípticum, Hook. Stem simple, herbaceous (10–20´ high), obscurely 4-angled; leaves spreading, elliptical-oblong, obtuse, usually narrower toward the subclasping base, thin; cyme nearly naked, rather few-flowered; sepals oblong; pods ovoid, very obtuse; seeds minutely striate.—Wet places, New Eng. and Penn. to Minn., and northward. July, Aug.—Petals light yellow, 3´´ long.
10. H. virgàtum, Lam. Stem slender, strict, simple, sharply 4-angled, herbaceous (1–2° high); leaves ascending, opaque, ovate or oblong-lanceolate, acute (½–1´ long), closely sessile by a broad base; cyme compound, naked, the scattered flowers racemose on its ascending branches; sepals herbaceous, erect, enclosing the ovoid pod; styles 3, separate, with capitate stigmas. (H. angulosum, Michx.)—Wet pine barrens of N. J. and southward; Ky. July–Sept.—Petals copper-yellow, 4–5´´ long.
§ 3. Stamens very many, in 3 or 5 clusters; styles 3, separate and usually diverging; pod 3-celled; calyx erect; petals and anthers with black dots; perennials.
H. perforàtum, L. (Common St. John's-wort.) Stem much branched and corymbed, somewhat 2-edged (producing runners from the base); leaves elliptical-oblong or linear-oblong, with pellucid dots; petals (deep yellow) twice the length of the lanceolate acute sepals; flowers numerous, in open leafy cymes.—Fields, etc. June–Sept.—Too well known as a pernicious weed, which it is difficult to extirpate. Juice very acrid. (Nat. from Eu.)
11. H. maculàtum, Walt. Conspicuously marked with both black and pellucid dots; stem terete, sparingly branched; leaves oblong or lance-ovate, the base either obtuse or somewhat clasping; flowers crowded (small); petals pale yellow, much longer than the oblong sepals, styles mostly not longer than the pod. (H. corymbosum, Muhl.)—Damp places; common. July–Sept.—Leaves larger and flowers much smaller than in the last; petals 2–3´´ long, marked with black lines as well as dots. The ordinary northern form differs from the typical southern one in the shorter style and the more oblong less clasping leaves.
§ 4. Stamens 5–12, distinct or in 3 clusters; pod 1-celled, with 3 strictly parietal placentæ; styles short, distinct, with capitate stigmas; petals oblong or linear; sepals narrow, erect; slender annuals, with 4-angular branches; flowering all summer.
[*] Stem simple or loosely branched; leaves linear to ovate, spreading.
12. H. mùltilum, L. Stem flaccid, widely branching (6–20´ high); leaves ovate to narrowly oblong, obtuse, partly clasping, 5-nerved; cymes leafy; flowers 2´´ broad; pods ovate-conical, rather longer than the calyx.—Low grounds, everywhere.
13. H. gymnánthum, Engelm. & Gray. Almost simple, with strict stem and branches (1–3° high); leaves clasping, heart-shaped, acute or obtuse; cyme naked, the floral leaves reduced to small awl-shaped bracts; in aspect approaching the next. (H. mutilum, var. gymnanthum, Gray.)—Del. and Penn. to Minn., and southward.
14. H. Canadénse, L. Stem strict (6–15´ high), with the branches erect; leaves linear, 3-nerved at the base, obtuse; cymes naked; flowers deep yellow, 2–3´´ broad when expanded; pods conical-oblong, usually much longer than the calyx.—Wet, sandy soil; common. June–Oct.—Var. màjus, Gray, is a large form, 1–2° high, with lanceolate leaves 1½´ long, 3´´ wide, the upper acute. L. Superior, Robbins; S. New York and southward.—Var. minimum, Chois., a simple few-flowered form, 1–3´ high, with oblong obtuse leaves. On wet rocks, Wisc., and northward.
[*][*] Stems fastigiately branched; leaves linear or bract-like, ascending or appressed.
15. H. Drummóndii, Torr. & Gray. Stem and the mostly alternate bushy branches rigid, erect (10–18´ high); leaves linear-subulate, nearly erect, 1-nerved (3–9´´ long); flowers scattered along the upper part of the leafy branches, short-pedicelled; pods ovoid, not longer than the calyx.—W. Ill., Iowa, Kan., and southward, in dry soil.
16. H. nudicaùle, Walt. (Orange-grass. Pine-weed.) Stem and bushy branches thread-like, wiry (4–9´ high); leaves minute awl-shaped scales, appressed; flowers minute, mostly sessile and scattered along the erect branches; pods ovate-lanceolate, acute, much longer than the calyx. (H. Sarothra, Michx.)—Sandy fields, N. Eng. to Ill., Mo., and southward; common. June–Oct.
3. ELÒDES, Adans. Marsh St. John's-wort.
Sepals 5, equal, erect. Petals 5, equal-sided, oblong, naked, imbricated in the bud. Stamens 9 (rarely more), united in 3 sets; the sets separated by as many large orange-colored glands. Pod 3-celled, oblong, styles distinct.—Perennial herbs, in marshes or shallow water, with small close clusters of flesh-colored flowers in the axils of the leaves and at the summit of the stem. (Name ἑλώδης, growing in marshes, accidentally changed to Elodèa by Jussieu, who was followed by Pursh, etc.)
1. E. campanulàta, Pursh. Leaves closely sessile or clasping by a broad base, oblong or ovate, very obtuse; filaments united below the middle. (E. Virginica, Nutt.)—Common in swamps; 1–2° high. July, Aug.
2. E. petiolàta, Pursh. Taller, more branching; leaves tapering into a short petiole, oblong; filaments united beyond the middle.—From Va. south and westward.