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round-fruit St. John's-wort, roundseed St. Johnswort

sparse-leaf St. Johnswort

Habit Herbs (perennial) or subshrubs, erect or decumbent, not or rarely rhizomatous, unbranched or branched proximally, 2–6 dm. Herbs perennial, erect to ascending, branching at ± aerenchymatous base and in inflorescence, 3–12 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.

ascending to appressed, sessile;

blade usually lanceolate, rarely elliptic to ovate, 5–20(–24) × 5–15 mm, shorter than internodes, smaller distally, leathery, margins plane, apex acute, gland-dotted, less conspicuously adaxially, basal veins 1–5, midrib with 2–3 pairs of branches.

Inflorescences

rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes.

corymbiform, to 30-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.

5–13 mm diam.;

sepals lanceolate, unequal, 3.5–4.2(–4.8) mm, margins sometimes ciliate, not setulose-ciliate, apex acute to subacuminate;

petals orange-yellow, ± obovate, 5–10 mm;

stamens 50–80, filaments basally connate;

styles 2–4 mm;

stigmas clavate.

Capsules

broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm.

ovoid, 3–4.5 mm.

Seeds

carinate, 2–2.7 mm;

testa coarsely reticulate.

0.4–0.7 mm;

testa reticulate.

Hypericum sphaerocarpum

Hypericum erythreae

Phenology Flowering summer (Jun–Aug). Flowering mid summer–fall (Jul–Oct).
Habitat Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments Bogs, ditches, coastal plain
Elevation 500–1000 m (1600–3300 ft) 0–300 m (0–1000 ft)
Distribution
from FNA
AL; AR; IA; IL; IN; KS; KY; MI; MO; MS; NE; OH; OK; TN; TX; WI; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
GA; SC
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.)

Source FNA vol. 6, p. 83. FNA vol. 6, p. 90.
Parent taxa Hypericaceae > Hypericum > sect. Myriandra Hypericaceae > Hypericum > sect. Brathys
Sibling taxa
H. adpressum, H. anagalloides, H. apocynifolium, H. ascyron, H. boreale, H. brachyphyllum, H. buckleyi, H. canadense, H. canariense, H. chapmanii, H. cistifolium, H. concinnum, H. crux-andreae, H. cumulicola, H. densiflorum, H. denticulatum, H. dolabriforme, H. drummondii, H. edisonianum, H. ellipticum, H. erythreae, H. fasciculatum, H. frondosum, H. galioides, H. gentianoides, H. graveolens, H. gymnanthum, H. harperi, H. hypericoides, H. kalmianum, H. lissophloeus, H. lloydii, H. lobocarpum, H. maculatum, H. majus, H. microsepalum, H. mutilum, H. myrtifolium, H. nitidum, H. nudiflorum, H. paucifolium, H. perforatum, H. prolificum, H. pseudomaculatum, H. punctatum, H. radfordiorum, H. scouleri, H. setosum, H. suffruticosum, H. tenuifolium, H. tetrapetalum, H. virgatum, H. ×mitchellianum
H. adpressum, H. anagalloides, H. apocynifolium, H. ascyron, H. boreale, H. brachyphyllum, H. buckleyi, H. canadense, H. canariense, H. chapmanii, H. cistifolium, H. concinnum, H. crux-andreae, H. cumulicola, H. densiflorum, H. denticulatum, H. dolabriforme, H. drummondii, H. edisonianum, H. ellipticum, H. fasciculatum, H. frondosum, H. galioides, H. gentianoides, H. graveolens, H. gymnanthum, H. harperi, H. hypericoides, H. kalmianum, H. lissophloeus, H. lloydii, H. lobocarpum, H. maculatum, H. majus, H. microsepalum, H. mutilum, H. myrtifolium, H. nitidum, H. nudiflorum, H. paucifolium, H. perforatum, H. prolificum, H. pseudomaculatum, H. punctatum, H. radfordiorum, H. scouleri, H. setosum, H. sphaerocarpum, H. suffruticosum, H. tenuifolium, H. tetrapetalum, H. virgatum, H. ×mitchellianum
Synonyms Brathydium chamaenerium, B. sphaerocarpum, H. chamaenerium, H. sphaerocarpum var. turgidum, H. turgidum Brathys erythreae
Name authority Michaux: Fl. Bor.-Amer. 2: 78. (1803) (Spach) Steudel: Nomencl. Bot. ed. 2, 1: 787. (1840)
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