Home Flora of Missouri
Name Search
!Hypericum L. Search in The Plant ListSearch in IPNISearch in Australian Plant Name IndexSearch in Index Nominum Genericorum (ING)Search in NYBG Virtual HerbariumSearch in JSTOR Plant ScienceSearch in SEINetSearch in African Plants Database at Geneva Botanical GardenSearch in Flora do Brasil 2020Search in Reflora - Virtual HerbariumSearch in Living Collections Decrease font Increase font Restore font

Published In: Species Plantarum 2: 783. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 8/11/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/30/2009)


Export To PDF Export To Word

1. Hypericum L. (St. John’s wort)

Plants annual or perennial herbs or shrubs. Young stems or twigs often angled, sometimes narrowly 2-winged. Leaves sessile, the blades sometimes clasping at the base. Flowers actinomorphic (except in H. hypericoides). Calyces of 4 or 5 sepals, these often persistent at fruiting. Corollas of 4 or 5 petals, these yellow, less commonly orangish yellow, usually somewhat asymmetric at the tip, sometimes withered but persistent at fruiting. Stamens 5 to more commonly numerous, the filaments free, fused basally into a short ring around the ovary base, or those of varying numbers of stamens fused basally into 3–5 sometimes indistinct groups. Staminodes absent. Pistils of 2–5 fused carpels. Ovary 1-locular with parietal placentation, or completely or incompletely 3–5-locular and then with more or less axile placentation. Style 1–5, if more than 1 then the styles sometimes fused basally or closely appressed to each other most of their length, the stigmas capitate or minute. Fruits capsules, narrowly to broadly ovoid, ellipsoid, conical or nearly globose. Seeds numerous (except in H. sphaerocarpum), tiny, ellipsoid-cylindrical to oblong-cylindrical. Three hundred to 400 species, nearly worldwide, but most diverse in temperate regions of the Northern Hemisphere.


Export To PDF Export To Word Export To SDD
Switch to indented key format
1 1. Plants shrubs, noticeably woody above the base

2 2. Sepals 2 or 4, the inner pair absent or much smaller than the outer pair; petals 4, pale yellow to lemon yellow ... 6. H. HYPERICOIDES

Hypericum hypericoides
3 2. Sepals 5, all of similar size and shape; petals 5, mostly bright yellow to orangish yellow

4 3. Fruits 5–7(–8) mm long, lobed longitudinally; styles mostly 4 or 5; ovaries and fruits appearing mostly 4- or 5-locular ... 7. H. LOBOCARPUM

Hypericum lobocarpum
5 3. Fruits 7–14 mm long, not lobed, circular or bluntly triangular in cross-section; styles 3(4); ovaries and fruits appearing 3(4)-locular ... 11. H. PROLIFICUM

Hypericum prolificum
6 1. Plants annual or perennial herbs, sometimes with a somewhat woody rootstock or with stems woody at the very base

7 4. Largest leaves scalelike or needlelike, 0.5–1.5 mm wide, with only a midvein visible

8 5. Leaves 5–22 mm long, linear, needlelike; fruits as long as or slightly longer than the sepals at maturity ... 3. H. DRUMMONDII

Hypericum drummondii
9 5. Leaves 1–4 mm long, triangular to ovate, scalelike; fruits 2–3 times as long as the sepals at maturity ... 4. H. GENTIANOIDES

Hypericum gentianoides
10 4. Largest leaves variously shaped, but not scalelike or needlelike, 2–20 mm wide, if linear then with (3)5 or 7 main veins from the leaf base

11 6. Petals 25–30 mm long; styles 5; ovary and fruit 5-locular, the fruits 15–35 mm long; seeds winged; stems (50–)70–200 cm long ... 2. H. ASCYRON

Hypericum ascyron
12 6. Petals 1.5–25.0 mm long; styles 1 or 3(4); ovary and fruit 1- or 3(4)-locular, the fruits 2–12 mm long; seeds not winged; stems 10–80 cm long

13 7. Sepals and/or petals with noticeable yellowish brown to black dots, lines, and/or streaks (these sometimes difficult to observe in fruiting material); petals withered and inconspicuous but usually persistent at fruiting; fruits completely 3-locular (sometimes incompletely so at the very tip)

14 8. Upper portion of the stem sharply ridged below each leaf; sepals usually with few yellowish brown to black dots; petals with black dots usually relatively few and restricted to at or near the margins ... 10. H. PERFORATUM

Hypericum perforatum
15 8. Stem rounded or bluntly and inconspicuously angled below each leaf; sepals and petals with yellowish brown to black dots, lines, and/or streaks abundant and occurring irregularly across the entire surface

16 9. Sepals 5–7 mm long; petals 8–12 mm long; uppermost leaves ovate to broadly triangular-ovate (those farther down the stem narrowly ovate to narrowly elliptic), mostly sharply pointed at the tip ... 12. H. PSEUDOMACULATUM

Hypericum pseudomaculatum
17 9. Sepals 2.5–4.0 mm long; petals 4–8 mm long; leaves oblong-elliptic to narrowly oblong or oblanceolate, rounded to less commonly bluntly pointed at the tip ... 13. H. PUNCTATUM

Hypericum punctatum
18 7. Sepals and/or petals lacking yellowish brown to black dots, lines, or streaks; petals usually shed by fruiting; fruits 1-locular or appearing partially 3-locular by intrusion of the marginal placentae into the locule

19 10. Petals 5–9 mm long; stamens 45–85; styles erect, appressed to each other and sometimes fused toward the base, the stigmas minute

20 11. Plants with long-creeping rhizomes bearing scattered aerial stems, the rootstocks entirely herbaceous; fruits (below the persistent styles) ellipsoid to ovoid; seeds numerous, 0.6–0.8 mm long ... 1. H. ADPRESSUM

Hypericum adpressum
21 11. Plants with short, poorly developed rhizomes or these more commonly lacking, the aerial stems occurring singly or more commonly 2 or more together, the rootstocks and stem bases often somewhat woody; fruits (below the persistent styles) broadly ovoid to more or less globose; seeds 4–8 per fruit, 2.0–2.7 mm long ... 14. H. SPHAEROCARPUM

Hypericum sphaerocarpum
22 10. Petals 1.5–5.0 mm long; stamens 5–20; styles spreading to ascending, not appressed or fused except sometimes at the base, the stigmas capitate

23 12. Fruits ellipsoid, widest at about the midpoint; sepals linear-lanceolate to narrowly oblong-lanceolate; petals 1.5–2.5 mm long; leaves rounded to bluntly pointed at the tip ... 9. H. MUTILUM

Hypericum mutilum
24 12. Fruits ovoid or conical, widest well below the midpoint; sepals lanceolate; petals 3.5–5.0 mm long; at least the uppermost leaves sharply pointed at the tip

25 13. Leaves lanceolate-triangular to ovate-triangular, broadly rounded to shallowly cordate at the base; plants annual, lacking rhizomes or the remains of previous years’ growth; stamens 10–15; fruits 3–5 mm long, narrowly ovoid ... 5. H. GYMNANTHUM

Hypericum gymnanthum
26 13. Leaves lanceolate to narrowly elliptic or narrowly oblong, narrowed or narrowly rounded at the base; plants perennial, sometimes with short rhizomes, the rootstock usually with the persistent remains of previous years’ growth; stamens 14–20; fruits 5–7 mm long, ovoid-conical ... 8. H. MAJUS Hypericum majus
© 2017 Missouri Botanical Garden - 4344 Shaw Boulevard - Saint Louis, Missouri 63110