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.