The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

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

brushy mountain St. Johnswort

Habit Herbs (perennial) or subshrubs, erect or decumbent, not or rarely rhizomatous, unbranched or branched proximally, 2–6 dm. Herbs perennial, erect or ± spreading, branching at base and beyond, (3–)4–7(–7.8) 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 widely spreading, sessile;

blade narrowly lanceolate (linear-lanceolate on axillary branches), 10–40(–55) × 5–10(–13) mm, longer than internodes, leathery, margins plane, apex acute to acuminate, densely gland-dotted, basal vein 1, midrib with inconspicuous branches.

Inflorescences

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

cylindric, to 40-flowered; branching mostly dichasial, subsidiary branches usually with relatively smaller leaves.

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.

8–15+ mm diam.;

sepals lanceolate, unequal (outer slightly wider than inner), 3–6(–7.5) × 1.1–1.8(–2.2) mm, margins sometimes ciliate, not setulose-ciliate, apex acute or acuminate;

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

stamens 50–80, filaments basally connate;

styles 2–4 mm;

stigmas capitate.

Capsules

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

ovoid, 5 × 3–4 mm.

Seeds

carinate, 2–2.7 mm;

testa coarsely reticulate.

0.4–0.8 mm;

testa linear-pitted.

2n

= 24.

Hypericum sphaerocarpum

Hypericum radfordiorum

Phenology Flowering summer (Jun–Aug). Flowering late spring–fall (May–)Jun–Sep(–Oct).
Habitat Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments Granitic outcrops
Elevation 500–1000 m (1600–3300 ft) 500–800 m (1600–2600 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
NC
[BONAP county map]
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. 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. 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
Name authority Michaux: Fl. Bor.-Amer. 2: 78. (1803) Weakley ex J. R. Allison: Castanea 76: 110, fig. 3. (2011)
Web links