Flora of North America species comparison

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Hypericum perforatum

Hypericum sect. Hypericum

Chase-devil, common St. John's-wort, Klamath weed, millepertuis commun, Tipton's weed
Habit Herbs, perennial, [subshrubs]; black glands usually on leaves, sepals, and petals and, sometimes, on stems and anthers.
Leaves

persistent or tardily deciduous, (base not articulated).
Flowers

6–35 mm diam.;

sepals persistent, 5;

petals persistent, 5;

stamens persistent, 20–109, in 5 fascicles, fascicles connate as 2 + 2 + 1;

ovary 3(–4)-merous;

placentation axile;

styles spreading, bases distinct;

stigmas relatively small.
Seeds

not or slightly carinate.
Species

22 (8, including 1 hybrid, in the flora): North America, Mexico, West Indies, Central America, South America.

Hypericum perforatum

Hypericum sect. Hypericum
Distribution
from FNA
AR; CA; CO; CT; DC; DE; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; Europe; Asia (sw Arabia, China, India, Mongolia, Siberia); n Africa [Also introduced widely elsewhere]
[WildflowerSearch map]
[BONAP county map]
North America; Mexico; Central America; South America; West Indies
Discussion

Subspecies 4 (1 in the flora).

Hypericum perforatum has been introduced into various parts of the world, including North America, where only subsp. perforatum is represented. The range of variation in the flora area is less than occurs in Europe, and signs of hybridization that are common there are absent in North America.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 22 (8 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Herbs rarely with rooting base, bushy; leaf blades usually conduplicate; sepals markedly imbricate.
H. concinnum
1. Herbs usually with rooting base (except H. punctatum), not bushy; leaf blades not conduplicate; sepals not or scarcely imbricate.
→ 2
2. Stems with black glands in raised lines or without black glands; leaf blades: tertiary veins not densely reticulate, black glands intramarginal, (± dense to spaced), and laminar, (relatively few and distal or absent); capsules ovoid, broadly ovoid, narrowly ovoid-pyramidal, or oblanceoloid
→ 3
2. Stems with black glands scattered on or near lines or all over; leaf blades: tertiary veins densely reticulate toward margins, black glands intramarginal (dense) and laminar (scattered); capsules ellipsoid, ovoid, broadly ovoid, or subglobose
→ 5
3. Stems from rooting, creeping base, internodes weakly 2-lined or not lined, without black glands, rarely with reddish glands; petals sometimes red-tinged.
H. scouleri
3. Stems from rooting, not creeping, base, internodes 2- or 4-lined, with black glands in lines; petals not red-tinged
→ 4
4. Stems: internodes (at least some) 4-lined; sepals broadly ovate to oblong, apex rounded-apiculate to erose-denticulate; capsules with longitudinal vittae (narrow linear glands).
H. maculatum
4. Stems: internodes 2-lined; sepals lanceolate or narrowly oblong to linear, apex acute to aristate; capsules with longitudinal vittae and shorter, oblique vittae.
H. perforatum
5. Leaf blade apex usually acute, rarely obtuse to rounded; inflorescence subsidiary branches ascending to widely spreading; anther gland amber or pellucid.
H. pseudomaculatum
5. Leaf blade apex usually obtuse, rounded, retuse, or subretuse, rarely acute; inflorescence subsidiary branches narrowly ascending or curved-ascending; anther gland black
→ 6
6. Inflorescences (2–)5–14(–22)-flowered; petals 11–18 mm; styles 5.6–12 mm.
H. graveolens
6. Inflorescences (5–)13–600-flowered; petals 3–11 mm; styles 1–5 mm
→ 7
7. Stems with black glands on or near lines or all over; flowers 15–20 mm diam.; capsules with longitudinal vittae.
H. ×mitchellianum
7. Stems with black glands scattered; flowers 8–15 mm diam.; capsules with longitudinal vittae or elongate to ovoid vesicles.
H. punctatum
Source FNA vol. 6, p. 99. FNA vol. 6, p. 97.
Parent taxa Hypericaceae > Hypericum > sect. Hypericum Hypericaceae > Hypericum
Sibling taxa
H. adpressum, H. anagalloides, H. apocynifolium, H. ascyron, H. boreale, H. brachyphyllum, H. buckleyi, H. canadense, H. canariense, H. chapmanii, H. cistifolium, H. concinnum, H. crux-andreae, H. cumulicola, H. densiflorum, H. denticulatum, H. dolabriforme, H. drummondii, H. edisonianum, H. ellipticum, H. erythreae, H. fasciculatum, H. frondosum, H. galioides, H. gentianoides, H. graveolens, H. gymnanthum, H. harperi, H. hypericoides, H. kalmianum, H. lissophloeus, H. lloydii, H. lobocarpum, H. maculatum, H. majus, H. microsepalum, H. mutilum, H. myrtifolium, H. nitidum, H. nudiflorum, H. paucifolium, H. prolificum, H. pseudomaculatum, H. punctatum, H. radfordiorum, H. scouleri, H. setosum, H. sphaerocarpum, H. suffruticosum, H. tenuifolium, H. tetrapetalum, H. virgatum, H. ×mitchellianum
Subordinate taxa
H. perforatum subsp. perforatum
H. concinnum, H. graveolens, H. maculatum, H. perforatum, H. pseudomaculatum, H. punctatum, H. scouleri, H. ×mitchellianum
Synonyms H. section Concinna, H. section Graveolentia
Name authority Linnaeus: Sp. Pl. 2: 785. (1753) unknown
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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