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mountain St. Johnswort

Habit Herbs perennial, semiaquatic or aquatic, erect, branching with long-creeping rhizomes at aerenchymatous base and from mid and distal nodes, 3–10 dm. Herbs erect, with rooting, creeping base, 3–6.5 dm.
Stems

internodes 4-lined.

internodes 4-lined at first, soon 2-lined, with black glands on or near lines.

Leaves

ascending to deflexed, sessile;

blade narrowly oblong-elliptic (proximal) or lanceolate to linear-lanceolate, 10–30 × 3–8 mm, mostly longer than internodes, not or scarcely smaller distally, leathery, margins plane, apex acute, basal or near-basal veins 1–3(–5), midrib with 0–2 pairs of branches.

spreading, sessile;

blade ovate to oblong or lanceolate, 33–65 × 15–27 mm, base cordate to truncate or broadly cuneate, margins plane, apex obtuse to rounded, midrib with 4–5 pairs of branches, tertiary veins densely reticulate toward margins, black glands intramarginal (dense) and, sometimes, laminar (scattered).

Inflorescences

broadly pyramidal to subcorymbiform, 1(–30)-flowered, branching mostly dichasial.

subcorymbiform, (2–)5–14(–22)-flowered, subsidiary branches sometimes narrowly ascending or curved-ascending.

Flowers

4–10 mm diam.;

sepals lanceolate, usually unequal, 3–5 × 0.8–1 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to acuminate;

petals orange-yellow, obovate, 6–10 mm;

stamens 50–80, irregularly grouped;

styles 2–4 mm;

stigmas capitate.

20–25(–30) mm diam.;

sepals not imbricate, erect in fruit, lanceolate, subequal, 5–7.5(–11) × 1–3 mm, apex acute;

petals golden yellow, narrowly obovate, 11–18 mm;

stamens 50–90(–103);

anther gland black;

styles 5.6–12 mm.

Capsules

ellipsoid to rostrate-subglobose, 3–4.5 × 2–2.5 mm.

broadly ovoid, 5–8 × 3.5–5 mm, with longitudinal vittae.

Seeds

0.5–0.6(–0.7) mm;

testa obscurely linear-reticulate to irregularly reticulate.

not carinate, 0.8–1.1 mm;

testa linear-reticulate.

2n

= 24.

= 16.

Hypericum harperi

Hypericum graveolens

Phenology Flowering mid–late summer (Jul–Sep). Flowering summer (Jun–Aug).
Habitat Open Taxodium swamps, wet pine barrens Open or partly shaded, moist habitats, dry, rocky roadside banks
Elevation 0–200 m (0–700 ft) 1200–2100 m (3900–6900 ft)
Distribution
from FNA
AL; FL; GA; SC
[BONAP county map]
from FNA
NC; TN
[WildflowerSearch map]
[BONAP county map]
Discussion

The chromosome count of n = 16 by Adams (in N. K. B. Robson and W. P. Adams 1968) is now regarded as an error; see D. E. Culwell (1970).

Hypericum graveolens is a relict species with close relatives in Japan; it hybridizes with H. ×mitchellianum and, probably, also with H. punctatum.

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

Source FNA vol. 6, p. 90. FNA vol. 6, p. 100.
Parent taxa Hypericaceae > Hypericum > sect. Brathys Hypericaceae > Hypericum > sect. Hypericum
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. 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
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. 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
Name authority R. Keller: Bot. Jahrb. Syst. 58: 198. (1923) Buckley: Amer. J. Sci. Arts 45: 174. (1843)
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