Hypericum mutilum subsp. mutilum |
Hypericum |
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dwarf st john's wort, millepertuis nain, small Canadian St. John's-wort |
millepertuis, St. Andrew's cross, St. John's-wort |
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Habit | Herbs, annual or perennial, subshrubs, or shrubs [trees], sometimes rhizomatous, glabrous or hairy, with glandular canals, lacunae, or dots containing resins or waxes (amber), essential oils (pale, translucent), and/or, sometimes, hypericin and pseudohypericin (black or red) in various parts. | |||||||||||||||||
Stems | apical internode shorter than adjacent one or almost absent. |
internodes terete (not lined) or 2-, 4-, or 6-lined at first (lines usually raised), then sometimes becoming angled, terete, or winged; bark smooth or striate, sometimes corky, punctiform. |
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Leaf | blades variable, rarely broadly ovate or suborbiculate. |
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Inflorescences | branching from 2–10 nodes, mostly dichasial. |
terminal, cymose, 2+-flowered, or flowers solitary, branching stellate [cupulate]; sepals persistent or deciduous, (3–)4–5, distinct or ± connate, margins sometimes glandular-ciliate; petals persistent or deciduous, (3–)4–5[–6], contorted, yellow to orange, sometimes red-tinged; stamens persistent or deciduous, (5–)10–300(–650), in continuous or interrupted ring or in (3–)4–5 fascicles, fascicles distinct or connate, each with 1–60+ stamens; filaments distinct or basally connate; anthers yellow to orange, oblong to ellipsoid, almost isodiametric, sometimes with amber or black gland on connective; staminode fascicles 0 [3]; ovary 2–5-merous; placentation axile to parietal; ovules 2+ on each placenta; styles distinct or ± connate basally, spreading to ± appressed. |
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Capsules | 2–5-valved, sometimes with glandular vittae or vesicles. |
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Seeds | narrowly cylindric to ellipsoid, sometimes carinate; testa foveolate or reticulate to scalariform [papillose]. |
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Sepals | not imbricate or broader beyond middle or, if imbricate, leaves not broadly ovate to suborbiculate. |
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x | = 12, 9–7, 6 (dihaploid). |
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2n | = 16. |
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Hypericum mutilum subsp. mutilum |
Hypericum |
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Phenology | Flowering summer–fall (Jun–Oct). | |||||||||||||||||
Habitat | Ditches, marshes, lake margins, desiccated temporary pools | |||||||||||||||||
Elevation | 0–400 m (0–1300 ft) | |||||||||||||||||
Distribution |
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 [Widely introduced in Central America, South America, Europe, Pacific Islands (Hawaii, New Zealand)] |
Nearly worldwide |
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Discussion | The records of subsp. mutilum from British Columbia and Saskatchewan and from California, Colorado, Oregon, and Utah (no details seen) are almost certainly all the result of introduction, as may be some other peripheral records. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species ca. 490 (54 in the flora). Shrubs with deciduous leaves, petals, and stamens belong to either Hypericum sect. Ascyreia Choisy (with five stamen fascicles and five styles) or sect. Androsaemum (Duhamel) Godron (with five stamen fascicles and three or four styles). These are all introductions, mostly garden escapes. Those in sect. Ascyreia include: Hypericum calycinum Linnaeus, a low shrub with creeping stolons and flowers 50–95 mm diam. that has been found in California, Oregon, and Washington; H. ×moserianum Luquet ex André, its hybrid with H. patulum Thunberg, a low (sterile?) branching shrub with red anthers; and H. hookerianum Wight & Arnott, a shrub to 2 m tall with narrow leaves and a dense ring of relatively short stamens, recorded from California (its identity requires confirmation). In sect. Androsaemum, H. androsaemum is a deciduous shrub with relatively small flowers and baccate fruits that ripen from cherry-red to black; it has been found in British Columbia and in California and Washington. Introduced herbaceous species with three stamen fascicles and three styles include: Hypericum hirsutum, with hairy stems and leaves (Ontario); H. tetrapterum, with four-winged internodes and lanceolate sepals (British Columbia and Washington); H. pulchrum with cordate leaves and red-tinged petals (Newfoundland, St. Pierre and Miquelon); and H. humifusum Linnaeus, a procumbent herb with unequal sepals (British Columbia). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 6, p. 94. | FNA vol. 6, p. 72. | ||||||||||||||||
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Synonyms | Brathys euphorbioides, B. quinquenervia, H. euphorbioides, H. mutilum var. densiflorum, H. mutilum var. foliosissimum, H. mutilum var. minimum, H. mutilum var. parviflorum, H. quinquenervium | Ascyrum, Crookea, Sanidophyllum, Sarothra | ||||||||||||||||
Name authority | unknown | Linnaeus: Sp. Pl. 2: 783. (1753): Gen. Pl. ed. 5, 341. (1754) | ||||||||||||||||
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