Flora of North America species comparison

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Hypericum perforatum

Hypericum denticulatum

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

coppery St. John's wort
Habit Herbs perennial, erect, branching at usually aerenchymatous base and in inflorescence, 2–7 dm.
Stems

internodes 4-lined.
Leaves

(main stem) spreading to appressed, sessile;

blade usually broadly to narrowly ovate, rarely elliptic or lanceolate, 4–20 × 5–15(–18) mm, mostly shorter than internodes, leathery, margins plane, apex acute to subrounded, densely gland-dotted, basal veins 1–5, if 1, midrib with 2–3 pairs of branches.
Inflorescences

broadly pyramidal to corymbiform, to 25-flowered, branching mostly dichasial.
Flowers

5–13 mm diam.;

sepals ovate or lanceolate to elliptic or obovate, subequal, 3–8 × 1.5–4 mm, margins sometimes ciliate, not setulose-ciliate, apex acute;

petals orange-yellow, obovate, 5–10 mm;

stamens 50–80, irregularly grouped;

styles 2–4 mm;

stigmas clavate.
Capsules

ovoid to rostrate-subglobose, 3–5 × 2–3 mm.
Seeds

0.4–0.7 mm;

testa obscurely linear-reticulate to finely ribbed-scalariform.

Hypericum perforatum

Hypericum denticulatum
Phenology Flowering summer–early fall (Jun–Sep).
Habitat Wet woods, marshes, bogs
Elevation 0–400 m (0–1300 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; DE; GA; NC; NJ; NY; PA; SC; TN; VA
[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.)

D. H. Webb (1980) regarded the disjunct populations in North Carolina and Tennessee as possible relicts and the Alabama one as due to recent introduction. J. R. Allison (2011) agreed and, in his opinion, the Pennsylvania and Virginia records are historical, and Hypericum denticulatum is likely adventive in Georgia.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 6, p. 99. FNA vol. 6, p. 89.
Parent taxa Hypericaceae > Hypericum > sect. Hypericum Hypericaceae > Hypericum > sect. Brathys
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. 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. 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
Synonyms H. angulosum, H. denticulatum var. ovalifolium, H. laevigatum, H. virgatum var. ovalifolium
Name authority Linnaeus: Sp. Pl. 2: 785. (1753) Walter: Fl. Carol., 190. (1788)
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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