Hypericum sphaerocarpum |
Hypericum mutilum |
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round-fruit St. John's-wort, roundseed St. Johnswort |
dwarf St. John's-wort, small Canadian St. John's-wort, small flower st john's wort |
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Habit | Herbs (perennial) or subshrubs, erect or decumbent, not or rarely rhizomatous, unbranched or branched proximally, 2–6 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 2–4-lined. |
internodes 4-angled. |
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Leaves | blades narrowly elliptic or narrowly oblong to linear, 30–70 × 3–15 mm, base not articulated, narrowly cuneate to linear, margins plane to revolute, apex subacute to rounded, midrib with 0–4 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 | rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes. |
cylindric, 5–60-flowered, branching mostly dichasial; bracts linear-subulate. |
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Flowers | 10–15 mm diam.; sepals persistent, not enclosing capsule, 5, broadly ovate to oblong-elliptic, ± unequal, 2.5–5 × 1.5–3 mm; petals 5, bright yellow, oblanceolate-elliptic to elliptic, 5–9 mm; stamens persistent, 45–85; ovary 3-merous, placentation parietal. |
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 | broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm. |
narrowly ovoid to cylindric-ellipsoid, 2–5 × 1.6–2.4 mm, usually broadest at or near middle. |
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Seeds | carinate, 2–2.7 mm; testa coarsely reticulate. |
0.4–0.7 mm; testa finely linear-scalariform. |
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Hypericum sphaerocarpum |
Hypericum mutilum |
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Phenology | Flowering summer (Jun–Aug). | |||||
Habitat | Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments | |||||
Elevation | 500–1000 m (1600–3300 ft) | |||||
Distribution |
AL; AR; IA; IL; IN; KS; KY; MI; MO; MS; NE; OH; OK; TN; TX; WI; ON
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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 sphaerocarpum differs from H. cistifolium and H. nudiflorum in its semiherbaceous habit and more northwestern distribution, as well as in its combination of relatively long, narrow leaves, persistent sepals, globose and apiculate to rounded capsules, and relatively large seeds. The narrow-leaved, bushy form from eastern parts of the range (var. turgidum) merges with the typical form. (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. 83. | FNA vol. 6, p. 93. | ||||
Parent taxa | Hypericaceae > Hypericum > sect. Myriandra | Hypericaceae > Hypericum > sect. Brathys | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Brathydium chamaenerium, B. sphaerocarpum, H. chamaenerium, H. sphaerocarpum var. turgidum, H. turgidum | Sarothra mutila | ||||
Name authority | Michaux: Fl. Bor.-Amer. 2: 78. (1803) | Linnaeus: Sp. Pl. 2: 787. (1753) | ||||
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