Hypericum sphaerocarpum |
Hypericum canadense |
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round-fruit St. John's-wort, roundseed St. Johnswort |
Canadian St. John's-wort, lesser Canadian St. John's wort, lesser St. John's-wort, millepertuis de Canada |
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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, erect, basal branches relatively few or none, usually with strict, ascending branches from distal nodes, 0.3–7.5 dm. |
Stems | internodes 2–4-lined. |
internodes 4-angled. |
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. |
erect or spreading, sessile or subsessile; blade linear to oblanceolate-linear or (proximal) oblanceolate to obovate, 6–55 × 0.5–5.5 mm, papery to membranous, margins plane, apex rounded, basal or near-basal veins 1–3(–5), midrib with 1–4 pairs of branches. |
Inflorescences | rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes. |
corymbiform to cylindric, usually diffuse, 1–35-flowered, branching mostly dichasial. |
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. |
5–6 mm diam.; sepals linear-lanceolate to lanceolate, equal, 2.5–4.5 × 0.8–1 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to acuminate; petals golden yellow, sometimes red-veined, narrowly obovate to elliptic, 2.5–4 mm; stamens 12–25, obscurely 3–5-fascicled; styles 0.5–0.8 mm; stigmas broadly capitate. |
Capsules | broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm. |
narrowly conic to conic-cylindric, 4–6 × 1.5–3 mm, broadest proximal to middle. |
Seeds | carinate, 2–2.7 mm; testa coarsely reticulate. |
0.5–0.7 mm; testa finely linear-scalariform. |
2n | = 16. |
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Hypericum sphaerocarpum |
Hypericum canadense |
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Phenology | Flowering summer (Jun–Aug). | Flowering summer (Jun–Sep). |
Habitat | Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments | Fens, marshes, depressions, lake and pond margins |
Elevation | 500–1000 m (1600–3300 ft) | 0–500 m (0–1600 ft) |
Distribution |
AL; AR; IA; IL; IN; KS; KY; MI; MO; MS; NE; OH; OK; TN; TX; WI; ON
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CT; DC; DE; FL; GA; IA; IL; IN; KY; MA; MD; ME; MI; MN; MS; NC; NH; NJ; NY; OH; OR; PA; RI; SC; TN; VA; VT; WA; WI; WV; NB; NF; NS; ON; PE; QC; SPM [Introduced in Europe (Ireland, The Netherlands)]
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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.) |
Hypericum canadense is closely related to H. majus; it hybridizes with that species and with H. mutilum, producing intermediate forms. Hypericum ×dissimulatum E. P. Bicknell appears to comprise a continuous series of hybrids between H. canadense and H. mutilum or H. boreale such that it is not always possible to say which of these species is involved. Hypericum ×dissimulatum has been recorded from New Brunswick, Newfoundland, Nova Scotia, Ontario, and Quebec and from Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, and Virginia. J. Rousseau reduced Hypericum canadense var. minimum to a form; it does not seem to merit any recognition. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 83. | FNA vol. 6, p. 92. |
Parent taxa | Hypericaceae > Hypericum > sect. Myriandra | Hypericaceae > Hypericum > sect. Brathys |
Sibling taxa | ||
Synonyms | Brathydium chamaenerium, B. sphaerocarpum, H. chamaenerium, H. sphaerocarpum var. turgidum, H. turgidum | Brathys canadensis, H. canadense var. galiiforme, H. canadense var. magninsulare, H. canadense var. minimum |
Name authority | Michaux: Fl. Bor.-Amer. 2: 78. (1803) | Linnaeus: Sp. Pl. 2: 785. (1753) |
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