Herbs or shrubs, with opposite punctate or black-dotted leaves, and mostly cymose yellow flowers. Sepals 5, equal or nearly so. Petals 5, mainly oblique or contorted, convolute in the bud. Stamens ∞, distinct, or more or less united in clusters, sometimes with interposed hypogynous glands. Ovary I-celled, with 3-5 parietal placentae which sometimes project far into the cavity, or 3-5-celled (rarely 6-celled); ovules ∞, generally numerous; styles 3-6. Capsule 1-5-celled (rarely 6-celled). [The Greek name.]

About 210 species, of wide geographic distribution. In addition to the following, 12 others occur in southern and western North America. Type species: Hypericum perforatum L.

*Styles 5; large perennials; pods 5-celled.

Flowers 1'-2' broad; capsules 9"-10" long; plant herbaceous.

1.

H. Ascyron.

Flowers 6"-12" broad; capsules 3"-6" long; plant shrubby.

2.

H. Kalmianum,

** Styles 3 (rarely 4).

† Tall leafy shrubs.

Flowers numerous, 4"-8" wide; pods completely 3-celled.

Flowers 6"-8" broad; pods 4"-6" long.

3.

H. prolificum.

Flowers 4"-6" broad; pods 2"-3" long.

4.

H. densiflorum.

Flowers few or solitary, 1' -2' wide; pods incompletely 3-celled.

5.

H. aureum.

†† Herbaceous, sometimes woody at the base.

‡ Stamens numerous (15-40); flowers 3"-12" broad.

Capsules 1-celled or incompletely 3-4-celled.

Capsules incompletely 3-4-celled by the projecting placentae.

Leaves linear, 1"-2" wide.

6.

H. galioides.

Leaves oblong, 3" - 5" wide.

7.

H. adpressum.

Capsules strictly 1-celled; placentae parietal.

Styles united into a beak, separate above; stigmas minute.

Leaves linear or linear-oblong; seeds transversely rugose.

Nearly simple, erect; pod globose.

8.

H. cistifolium.

Branched, decumbent; pod 3-sided.

9.

H. dolabriforme.

Leaves elliptic; seeds minutely pitted and striate.

10.

H. ellipticum.

Styles separate; stigmas capitate; cyme naked.

11.

H. virgatum.

Capsules completely 3-celled; styles separate.

Leaves linear or oblong; sepals lanceolate; introduced.

12.

H. perforatum.

Leaves broadly oblong, oval or ovate-lanceolate; native species.

Sepals ovate to ovate-lanceolate.

Leaves obtuse; sepals acute; petals 2"-3" long.

13.

H.punctatum.

Leaves acute; sepals acuminate; petals 5"-10" long.

14.

H. pseudoinaculatum.

Sepals lanceolate; petals 5"-7" long; leaves obtuse.

15.

H. graveolens.

XX Stamens few (5-12); flowers 1/2"_3" broad.

Leaves spreading or ascending, 3-7-nerved.

Cyme leafy-bracted.

16.

H. boreale.

Cymes subulate-bracted.

Leaves ovate, oval, oblong or lanceolate, 5-7-nerved.

Leaves ovate, oval or oblong; capsule 1"-2 1/2" long.

Leaves obtuse; sepals linear-oblong, acutish or obtuse.

17.

H. mutilum.

Leaves acute, or only the lower obtuse; sepals long-acuminate.

18.

H. gymnanthum.

Leaves lanceolate or oblong-lanceolate; capsule 4"-5" long.

19.

H. majus..

Leaves linear, obtuse, 3-nerved.

20.

H. canadense.

Leaves linear, erect, 1-nerved.

21.

H. Drummondii.