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Key to Hypericum

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Show caption*© Sonnia Hill 1 Petals pale pink; stamens fascicled, in 3 fascicles of 3 stamens each; staminodia (hypogynous glands) present, alternating with the fascicles of stamens; perianth 5-merous  Triadenum

Show caption*© Alan M. Cressler 1 Petals yellow; stamens fascicled or not, if fascicled then not into 3 fascicles of 3 stamens each; staminodia (hypogynous glands) lacking; perianth 4-5-merous.

Show caption*© Scott Ward Show caption*© Scott Ward Show caption*© Scott Ward Show caption*© Scott Ward   2 Leaves with an articulation at the very base, this appearing as a narrow line, groove, or abrupt change of color and texture which extends across the petiole; shrubs; [section Myriandra].

3 Leaves needle-like, 0.5-1.5 (-2) mm wide, the margins essentially parallel (H. galioides keyed here and below); [subsection Centrosperma]  Key to Hypericum, Key A: shrubby St. John's-worts with needle-like leaves and flowers with 5 petals and 5 sepals [section Myriandra, subsection Centrosperma]

3 Leaves, at least the largest on the plant, not needle-like, wider than 2 mm, the margins not parallel, the widest point often beyond the middle.

4 Petals 4; sepals 4 (rarely 2); plant 5-100 cm tall; leaves 2-40 mm long; foliage bluish-green when fresh; [subsection Ascyrum]  Key to Hypericum, Key B: shrubby St. John's-worts with 4 petals and 4 (rarely 2) sepals [section Myriandra, subsection Ascyrum]

4 Petals 5; sepals 5; plant 50-250 cm tall; leaves (10-) 20-70 mm long; foliage green when fresh; [subsections Centrosperma and Brathydium]  Key to Hypericum, Key C: shrubby St. John's-worts with broader leaves (mostly lanceolate or oblanceolate) and flowers with 5 petals and 5 sepals

Show caption*© Scott Ward Show caption*© Scott Ward Show caption*© Scott Ward Show caption*© Scott Ward   2 Leaves without an articulation at the very base, the petiole merging gradually into the stem with no break, groove, or abrupt change in color or texture; herb, decumbent shrub, or shrub.

5 Leaves ascending or appressed, 1-nerved, < 1 mm wide; inflorescence either a compound raceme or a dichasial cyme; annual or perennial herbs; [section Brathys]  Key to Hypericum, Key D: herbaceous St. John's-worts with leaves ascending or appressed, 1-nerved, < 1 mm wide and with a diffuse, racemose or dichasial inflorescence

5 Leaves spreading or ascending, generally multi-nerved, > 1 mm wide; inflorescence a dichasial cyme; herbs or shrubs.

6 Leaves 1.5-5 cm wide; shrubs; [exotics persistent and sparingly naturalizing from horticultural cultivation]

7 Flowers 1.5-2.5 cm in diameter; fruit a fleshy berry, bright red turning black; sepals longer than the petals, spreading to reflexed in fruit; stems normally branching at the base and above  Hypericum androsaemum

7 Flowers 5-9.5 cm in diameter; fruit a dry, dehiscent capsule, green turning tan; sepals shorter than the petals, ascending in fruit; stems usually unbranched (clonal from creeping rhizomes)  Hypericum calycinum

6 Leaves < 1.5 cm wide; shrubs, subshrubs, suffrutescent herbs, and herbs; [natives and exotics, collectively common and widespread]

8 Capsule 5-locular; stamens connate basally into 5 fascicles; [section Roscyna]  Hypericum pyramidatum

8 Capsule 1-locular or 3 (-4) locular; stamens separate, connate basally into 3 or 5 fascicles, or connate but not into fascicles.

9 Capsule 3 (-4) locular; stamens connate at the base into 3 or 5 fascicles; leaves with black glandular dots as well as translucent glandular dots when backlit (except in H. perforatum); sepals and/or petals marked with black glandular dots or lines; perennial herbs; [section Hypericum]  Key to Hypericum, Key E: herbaceous St. John's-worts with broad leaves, 3 (-4) locular capsules, stamens connate at base into 3 or 5 fascicles, leaves with black dots as well as translucent glands (except in H. perforatum), and sepals and/or petals marked with black dots or lines

9 Capsule 1-locular; stamens separate or connate at the base, but not grouped into fascicles; leaves with translucent glandular dots, without black glandular dots (when backlit); sepals and petals with translucent glandular lines or dots only, not also marked with black glandular dots or lines.

10 Shrubs, decumbent shrubs, or suffruticose herbs; [section Myriandra, subsections Brathydium, Pseudobrathydium, and Suturosperma]  Key to Hypericum, Key F: shrubby and subshrubby St. John's-worts

10 Herbs; [section Trigynobrathys and section Myriandra subsection Suturosperma]  Key to Hypericum, Key G: herbaceous St. John's-worts with broad leaves, 1-locular capsules, stamens separate or connate at base, but not grouped into fascicles, leaves with translucent dots, without black dots, sepals and petals with translucent lines or dots only, not marked with black dots or lines