Hypericum sphaerocarpum |
Hypericum cumulicola |
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round-fruit St. John's-wort, roundseed St. Johnswort |
highlands scrub hypericum, highlands scrub 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. | Herbs perennial, erect, branching at or just below ground level and in inflorescence, 2–7.5 dm. |
Stems | internodes 2–4-lined. |
internodes 4-lined. |
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. |
appressed, sessile; blade linear-subulate, (1–)2.5–4 × 0.2–0.3 mm, subcoriaceous, margins incurved, apex acute, basal vein 1, midrib unbranched. |
Inflorescences | rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes. |
subcorymbiform, to 13-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. |
3–4 mm diam.; sepals ovate to elliptic or narrowly oblong, unequal, 1.5–2 × 0.6–1 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to subacute; petals yellow, obovate-oblong, 3.5–5 mm; stamens 20–25, irregularly arranged; styles 1.5–2 mm; stigmas capitate. |
Capsules | broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm. |
narrowly ovoid-conic, subrostrate, 3.5–6 × 1–1.5 mm. |
Seeds | carinate, 2–2.7 mm; testa coarsely reticulate. |
0.5–0.6 mm; testa scalariform-reticulate. |
2n | = 12. |
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Hypericum sphaerocarpum |
Hypericum cumulicola |
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Phenology | Flowering summer (Jun–Aug). | Flowering spring–late fall (Mar–Nov). |
Habitat | Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments | Scrub, on ancient white-sand dunes |
Elevation | 500–1000 m (1600–3300 ft) | 50 m (200 ft) |
Distribution |
AL; AR; IA; IL; IN; KS; KY; MI; MO; MS; NE; OH; OK; TN; TX; WI; ON
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FL
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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.) |
Of conservation concern. Hypericum cumulicola is confined to Highlands and Polk counties and its habitat is under threat from bulldozers and citrus groves (D. B. Ward 1980); its nearest relative, with the same chromosome number, appears to be H. setosum. Hypericum cumulicola is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 83. | FNA vol. 6, p. 91. |
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 | Sanidophyllum cumulicola |
Name authority | Michaux: Fl. Bor.-Amer. 2: 78. (1803) | (Small) W. P. Adams: Rhodora 64: 234. (1962) |
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