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brushy mountain St. Johnswort

Kalm's St. John's-wort, millepertuis de Kalm

Habit Herbs perennial, erect or ± spreading, branching at base and beyond, (3–)4–7(–7.8) dm. Shrubs, erect, forming slender to rounded or flat-topped bush, (1.4–)2–6(–10) dm.
Stems

internodes 4-lined.

internodes 4-lined at first, then terete.

Leaves

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.

blades narrowly oblong to oblanceolate or linear, (15–)20–45 × 3–7(–10) mm, base articulated, narrowly cuneate to subattenuate, margins subrecurved to revolute, apex rounded to obtuse, midrib with 9–14 pairs of branches.

Inflorescences

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

usually (1–)3–7(+)-flowered from apical node, rarely with flowers from 1–2 proximal nodes.

Flowers

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.

20–35 mm diam.;

sepals deciduous, not enclosing capsule, (4–)5, elliptic or oblong to obovate, subequal, 4–9 × 1.5–5 mm;

petals (4–)5, golden yellow, obovate to oblong, 8–15 mm;

stamens deciduous, 150–200;

ovary (3–)5(–6)-merous.

Capsules

ovoid, 5 × 3–4 mm.

narrowly ovoid-conic, 7–11 × 4–7 mm.

Seeds

0.4–0.8 mm;

testa linear-pitted.

narrowly carinate, 0.7–1.1 mm;

testa subscalariform.

2n

= 24.

= 18.

Hypericum radfordiorum

Hypericum kalmianum

Phenology Flowering late spring–fall (May–)Jun–Sep(–Oct). Flowering summer (Jul–Aug).
Habitat Granitic outcrops Sandy or calcareous dune slacks or swales, rocky shores, plains and low prairies, along streams, sphagnum-sedge swamps
Elevation 500–800 m (1600–2600 ft) 10–400 m (0–1300 ft)
Distribution
from FNA
NC
[BONAP county map]
from FNA
IL; IN; MI; NY; OH; WI; ON; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Hypericum kalmianum is a northern derivative of H. prolificum with shorter stems, narrower leaves, fewer and larger flowers, and, usually, five styles and placentae. Natural hybrids with H. prolificum have been reported from Wisconsin.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 6, p. 90. FNA vol. 6, p. 77.
Parent taxa Hypericaceae > Hypericum > sect. Brathys Hypericaceae > Hypericum > sect. Myriandra
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. scouleri, H. setosum, H. sphaerocarpum, 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. 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 Norysca kalmiana
Name authority Weakley ex J. R. Allison: Castanea 76: 110, fig. 3. (2011) Linnaeus: Sp. Pl. 2: 783. (1753)
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