1. H. Áscyron, L. (GREAT ST. JOHN'S-WORT.) Stems 2--5° high; branches 2--4-angled; leaves (2--5´ long) ovate-oblong, partly clasping; petals narrowly obovate (1´ long), not deciduous until after they wither; pod ¾´ long, conical. (H. pyramidatum, _Ait._)--Banks of rivers, New Eng. and Penn. to Iowa and Minn. July. § 2. _Stamens very numerous, obscurely if at all clustered; styles 3 (n. 2 excepted), more or less united into one, the stigmas not capitate except in n. 10; sepals mostly foliaceous._ [*] _Bushy shrubs, 1--6° high, leafy to the top._ [+] _Styles 5; pod completely 5-celled._ 2. H. Kalmiànum, L. (KALM'S ST. JOHN'S-WORT.) Branches 4-angled; branchlets 2-edged; leaves crowded, glaucous, linear to oblanceolate (1--2´ long); flowers few in a cluster (1´ wide); pods ovate.--Wet rocks, Niagara Falls and northern lakes. Aug. [+][+] _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.