Hypericum majus |
Hypericum mutilum |
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greater Canada St. John's-wort, greater Canadian St. John's-wort, large Canadian St. John's-wort, large St. John's wort, millepertuis majeur |
dwarf St. John's-wort, small Canadian St. John's-wort, small flower st john's wort |
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Habit | Herbs perennial, erect, branching at base and in inflorescence, branches relatively few, 0.5–7 dm. | Herbs annual or perennial, usually erect, sometimes decumbent and rooting, basal branches sometimes present, usually with to 10 pairs of spreading branches distal to middle, 0.5–8 dm. | ||||
Stems | internodes 4-angled. |
internodes 4-angled. |
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Leaves | spreading, sessile or distal subamplexicaul; blade lanceolate to narrowly oblong-elliptic or (proximal) oblanceolate, 10–45 × (2–)6–12 mm, papery to membranous, margins plane, apex acute to rounded, basal or near-basal veins (3–)5–7, midrib with to 4 pairs of branches. |
spreading, sessile or amplexicaul; blade paler abaxially, ovate, elliptic, or elliptic-oblong (proximal), ovate or suborbiculate to elliptic or lanceolate (mid and distal), 3–27(–40) × 1–15 mm, papery to membranous, margins plane, apex obtuse to rounded, basal veins 3–5, midrib with to 3 pairs of branches. |
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Inflorescences | corymbiform to cylindric, 3–30-flowered, usually compact, branching mostly dichasial. |
cylindric, 5–60-flowered, branching mostly dichasial; bracts linear-subulate. |
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Flowers | 6–7 mm diam.; sepals lanceolate to narrowly elliptic, equal, 3.5–6.5 × 0.8–1.5 mm, margins sometimes ciliate, not setulose-ciliate, apex acute; petals golden yellow, sometimes red-veined, oblanceolate, 3.5–6 mm; stamens 12–21, obscurely 5-fascicled; styles 0.6–1 mm; stigmas broadly capitate. |
3–5 mm diam.; sepals lanceolate to linear-lanceolate or elliptic-oblong to oblanceolate, equal or unequal, 2–4.5 × 0.6–1.5 mm, margins sometimes ciliate, not setulose-ciliate, apex usually acute to apiculate, sometimes obtuse to rounded; petals pale yellow, oblong, 1.7–3.5 mm; stamens 5–16, scarcely grouped; styles 0.5 mm; stigmas broadly capitate. |
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Capsules | narrowly conic-ellipsoid, 4–8 × 2.5–3.5 mm, broadest proximal to middle. |
narrowly ovoid to cylindric-ellipsoid, 2–5 × 1.6–2.4 mm, usually broadest at or near middle. |
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Seeds | 0.5–0.7 mm; testa finely linear-scalariform. |
0.4–0.7 mm; testa finely linear-scalariform. |
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2n | = 16. |
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Hypericum majus |
Hypericum mutilum |
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Phenology | Flowering summer (Jun–Sep). | |||||
Habitat | Fens, marshes, ditches, lake and stream margins, other damp habitats | |||||
Elevation | 0–1200 m (0–3900 ft) | |||||
Distribution |
CO; CT; IA; ID; IL; IN; KS; MA; ME; MI; MN; MO; MT; ND; NE; NH; NJ; NY; OH; OR; PA; RI; SD; VT; WA; WI; AB; BC; MB; NB; NS; ON; PE; QC; SK [Introduced in Europe (France, Germany), e Asia (Japan)]
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AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MS; NC; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; BC; NB; NS; ON; QC; SK [Introduced in w North America]
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Discussion | Hypericum majus was the western member of a vicariant species pair, differing from the originally eastern member (H. canadense) by the broader leaves, usually more-congested inflorescence, and larger flowers. These species became sympatric in glaciated northeastern North America and now hybridize freely, notably in Wisconsin (F. H. Utech and H. H. Iltis 1970). Hybrids are intermediate in form between the parents and have also been recorded from Connecticut, Massachusetts, and New Hampshire. Hypericum majus hybridizes also with H. mutilum, with subsp. mutilum in Maine, and with subsp. boreale in Michigan and Wisconsin. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 6, p. 91. | FNA vol. 6, p. 93. | ||||
Parent taxa | Hypericaceae > Hypericum > sect. Brathys | Hypericaceae > Hypericum > sect. Brathys | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | H. canadense var. majus, H. mutilum var. longifolium, Sarothra major | Sarothra mutila | ||||
Name authority | (A. Gray) Britton: Mem. Torrey Bot. Club 5: 225. (1894) | Linnaeus: Sp. Pl. 2: 787. (1753) | ||||
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