Hypericum sphaerocarpum |
Hypericum nudiflorum |
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round-fruit St. John's-wort, roundseed St. Johnswort |
early St. Johnswort, naked St. Johnswort |
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Habit | Herbs (perennial) or subshrubs, erect or decumbent, not or rarely rhizomatous, unbranched or branched proximally, 2–6 dm. | Subshrubs, erect, usually loosely branched with branches ascending, 5–20 dm. |
Stems | internodes 2–4-lined. |
internodes narrowly 4-winged at first, then terete. |
Leaf | 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. |
blades ovate-lanceolate or elliptic to linear-oblong, 30–70 × 7–25 mm, base not articulated, cuneate to subcordate, margins plane, apex obtuse to rounded, midrib with to 6 pairs of branches. |
Inflorescences | rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes. |
corymbiform to rounded-pyramidal, 7–45-flowered, narrowly branched, sometimes with 1–7(–40)-flowered dichasia from 1–3 proximal nodes. |
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. |
15–20 mm diam.; sepals deciduous, not enclosing capsule, 5, oblanceolate-spatulate to narrowly triangular, unequal to subequal, 2–5 × 1–1.5 mm; petals 5, pale or coppery yellow, oblanceolate-oblong to elliptic-oblong, 6–8(–10) × 3–4 mm, length 2–3 times sepals; stamens persistent, 80; ovary 3(–4)-merous, placentation incompletely axile. |
Capsules | broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm. |
broadly ellipsoid to ovoid-globose, 3.5–7 × 3–5 mm. |
Seeds | carinate, 2–2.7 mm; testa coarsely reticulate. |
markedly carinate, 1.5–2 mm; testa ± scalariform-reticulate. |
2n | = 18. |
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Hypericum sphaerocarpum |
Hypericum nudiflorum |
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Phenology | Flowering summer (Jun–Aug). | Flowering summer (Jun–late Aug). |
Habitat | Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments | Stream banks, moist woodland, swamps |
Elevation | 500–1000 m (1600–3300 ft) | 0–1000 m (0–3300 ft) |
Distribution |
AL; AR; IA; IL; IN; KS; KY; MI; MO; MS; NE; OH; OK; TN; TX; WI; ON
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AL; FL; GA; LA; MS; NC; SC; TN; VA
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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.) |
See under 15. Hypericum apocynifolium for differences between it and H. nudiflorum, which has a more eastern distribution. Records from Texas probably are referable to H. apocynifolium. Hypericum nudiflorum probably is now extirpated in Louisiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 83. | FNA vol. 6, p. 82. |
Parent taxa | Hypericaceae > Hypericum > sect. Myriandra | Hypericaceae > Hypericum > sect. Myriandra |
Sibling taxa | ||
Synonyms | Brathydium chamaenerium, B. sphaerocarpum, H. chamaenerium, H. sphaerocarpum var. turgidum, H. turgidum | Brathydium nudiflorum, Myriandra nudiflora |
Name authority | Michaux: Fl. Bor.-Amer. 2: 78. (1803) | Michaux ex Willdenow: Sp. Pl. 3: 1456. (1802) |
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