Hypericum sphaerocarpum |
Hypericum cistifolium |
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round-fruit St. John's-wort, roundseed St. Johnswort |
roundpod 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. | Shrubs, erect, unbranched or with relatively short branches and sometimes 1–2 branches ascending from proximal nodes, 5–13 dm. |
Stems | internodes 2–4-lined. |
internodes 4-lined 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 narrowly oblong or narrowly elliptic-oblong to triangular-lanceolate, 15–40 × 2–10 mm, base not articulated, cuneate to subcordate, margins recurved, apex subacute to rounded, midrib with 1 pair of branches. |
Inflorescences | rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes. |
corymbiform to cylindric, (7–)15–65-flowered, narrowly branched, sometimes with 3–65-flowered dichasia from 1–2 proximal nodes and relatively short, flowering branches from further 1–4 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. |
7–12 mm diam.; sepals persistent, not enclosing capsule, 5, obovate or broadly elliptic to oblong, unequal, 2–4 × 1–1.7 mm; petals 5, bright yellow, oblanceolate, 5–8 mm; stamens (some or all) persistent, 30–50; ovary 3-merous, placentation parietal. |
Capsules | broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm. |
ovoid-cylindric to broadly ovoid, 4–6 × 3–4 mm. |
Seeds | carinate, 2–2.7 mm; testa coarsely reticulate. |
not carinate, 0.6 mm; testa reticulate to linear-foveolate. |
2n | = 18. |
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Hypericum sphaerocarpum |
Hypericum cistifolium |
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Phenology | Flowering summer (Jun–Aug). | Flowering spring–early fall (Apr–Oct). |
Habitat | Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments | Pine flatwoods, margins of bogs, swamps, and marshes, ditches, on sand, coastal plain |
Elevation | 500–1000 m (1600–3300 ft) | 0–300 m (0–1000 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; TX
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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 cistifolium is woodier in habit than H. sphaerocarpum and has shorter leaves, smaller flowers, narrower sepals, narrower capsules, and smaller seeds. (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 | H. opacum, H. punctulosum, H. rosmarinifolium |
Name authority | Michaux: Fl. Bor.-Amer. 2: 78. (1803) | Lamarck: in J. Lamarck et al., Encycl. 4: 158. (1797) |
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