Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Hypericum perforatum

Hypericum prolificum

Chase-devil, common St. John's-wort, Klamath weed, millepertuis commun, Tipton's weed

shrubby St. John's-wort
Habit Shrubs, erect or ± diffuse, forming rounded or irregular bush, (2–)7.5–15(–20) dm.
Stems

internodes 4-lined at first, then 2-lined to terete.
Leaf

blades narrowly oblong to narrowly elliptic-oblanceolate, 30–70 × 6–15 mm, base articulated, attenuate to narrowly cuneate, margins plane to recurved, apex rounded-apiculate to acute, midrib with 10–16 pairs of branches.
Inflorescences

cylindric, (1–)3–7(–9)-flowered from apical node, with paired single flowers or triads or 1–3(–7)-flowered branches from 2+ proximal nodes.
Flowers

15–30 mm diam.;

sepals deciduous, not enclosing capsule, 5, elliptic to obovate or oblanceolate-spatulate, unequal or subequal, 4–8 × 1.5–4 mm;

petals 5, golden yellow, obovate to oblanceolate-spatulate, 7–15 mm;

stamens deciduous, 150–500;

ovary 3(–5)-merous, placentation incompletely axile.
Capsules

usually narrowly ovoid-conic to ovoid, rarely ellipsoid, 7–13 × 4–7 mm.
Seeds

carinate, 1.5–2 mm;

testa linear-reticulate.
2n

= 18.

Hypericum perforatum

Hypericum prolificum
Phenology Flowering summer (Jun–Sep).
Habitat Rocky slopes, embankments, dry stream bottoms, woodland (in north), on limestone or granite
Elevation 50–600+ m [160–2000+ ft]
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]
from FNA
AL; AR; DC; DE; FL; GA; IA; IL; IN; KY; LA; MD; MI; MO; MS; NC; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WI; WV; ON
[WildflowerSearch map]
[BONAP county map]
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.)

Hypericum prolificum is variable, the most luxuriant form being found in the southwestern part of its range. Natural hybrids have not been recorded; it hybridizes in gardens with H. densiflorum (H. x\arnoldianum Rehder), H. frondosum, H. kalmianum, and H. lobocarpum (H. x\dawsonianum Rehder).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 6, p. 99. Treatment author: Norman K. B. Robson. FNA vol. 6, p. 76. Treatment author: Norman K. B. Robson.
Parent taxa Hypericaceae > Hypericum > sect. Hypericum Hypericaceae > Hypericum > sect. Myriandra
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
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. perforatum, 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
Synonyms Brathys prolifica, H. spathulatum, Myriandra ledifolia, M. prolifica, M. prolifica var. spathulata, M. spathulata
Name authority Linnaeus: Sp. Pl. 2: 785. (1753) Linnaeus: Mant. Pl. 1: 106. (1767)
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).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Apiaceae, Boraginaceae, and Polemoniaceae.)

The species comparison tool is brought to you by:
Northwest Wildflowers