Hypericum cistifolium |
Hypericum gymnanthum |
|
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roundpod St. Johnswort |
claspingleaf St. Johnswort, small-flower St. John's wort |
|
Habit | Shrubs, erect, unbranched or with relatively short branches and sometimes 1–2 branches ascending from proximal nodes, 5–13 dm. | Herbs annual, usually erect, sometimes shortly decumbent and rooting, basal branches none, rarely with 1–3(–6) pairs of narrowly ascending branches distally, 0.6–7 dm. |
Stems | internodes 4-lined at first, then terete. |
internodes 4-angled. |
Leaves | 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. |
spreading, sessile or amplexicaul; blade usually ovate-triangular to broadly ovate, rarely oblong (mid and distal blades lanceolate-deltate), 5–25 × 3–12 mm, papery to membranous, margins plane, apex usually subacute, basal veins (3–)5, midrib usually with 1–2 pairs of branches. |
Inflorescences | 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. |
laxly corymbiform to cylindric, (1–)5–65-flowered, branching mostly dichasial. |
Flowers | 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. |
4.5–7 mm diam.; sepals lanceolate to narrowly ovate, equal, 3–5 × 0.8–1.2 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to acuminate; petals bright yellow, oblanceolate, 2–4 mm; stamens 10–14, scarcely grouped; styles 0.5–0.7 mm; stigmas broadly capitate. |
Capsules | ovoid-cylindric to broadly ovoid, 4–6 × 3–4 mm. |
narrowly conic-ellipsoid, 3–5 × 1.5–2 mm, usually broadest at or near middle. |
Seeds | not carinate, 0.6 mm; testa reticulate to linear-foveolate. |
0.5–0.6 mm; testa finely linear-scalariform. |
2n | = 18. |
= 16. |
Hypericum cistifolium |
Hypericum gymnanthum |
|
Phenology | Flowering spring–early fall (Apr–Oct). | Flowering summer (Jun–Sep). |
Habitat | Pine flatwoods, margins of bogs, swamps, and marshes, ditches, on sand, coastal plain | Bogs, ditches, open and cleared woods, damp habitats |
Elevation | 0–300 m (0–1000 ft) | 0–400 m (0–1300 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX
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AL; AR; DE; FL; GA; IL; IN; LA; MD; MO; MS; NC; NJ; OH; PA; SC; TN; TX; VA; Central America (Guatemala) [Introduced Atlantic Islands (Azores)]
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Discussion | 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.) |
Hypericum gymnanthum was introduced into Poland; it is now extinct there. It is closely related to H. mutilum; it differs from that species in the broader, usually deltate leaves; fewer, stricter branches; no condensed apical stem internode; and larger flowers with lanceolate to ovate sepals. Hybrids of Hypericum gymnanthum with H. mutilum have been reported from Maryland, Mississippi, North Carolina, Tennessee, and West Virginia, and, perhaps erroneously, with H. canadense from Virginia. Hypericum gymnanthum has clearly been introduced (recently?) into the Azores, not necessarily by man. Seeds may well have been carried there by birds. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 82. | FNA vol. 6, p. 93. |
Parent taxa | Hypericaceae > Hypericum > sect. Myriandra | Hypericaceae > Hypericum > sect. Brathys |
Sibling taxa | ||
Synonyms | H. opacum, H. punctulosum, H. rosmarinifolium | H. canadense var. cardiophyllum, H. mutilum var. gymnanthum, Sarothra gymnantha |
Name authority | Lamarck: in J. Lamarck et al., Encycl. 4: 158. (1797) | Engelmann & A. Gray: Boston J. Nat. Hist. 5: 212. (1845) |
Web links |