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Photo is of parent taxon

millepertuis à grandes fleurs

great or giant St. John's wort, great St. John's-wort

Habit Herbs erect, branched from base and often with strict, narrowly ascending branches, 5–20 dm.
Stems

internodes 4-lined at first, then 4-angled.

Leaves

spreading, sessile, amplexicaul;

blade ovate-lanceolate to lanceolate or oblong, 40–85 × 18–37 mm on main stem, smaller distally and on branches, base rounded to cordate, margins plane, apex usually acute to apiculate, sometimes obtuse, midrib with 4–7 pairs of branches, tertiary veins densely reticulate toward margins.

Inflorescences

cylindric to narrowly pyramidal, 1–35-flowered.

Flowers

sepals ovate to lanceolate or oblong-elliptic, subequal or equal, 8–13 × 4–8 mm, apex acute to acuminate;

petals golden yellow, sometimes red-tinged, narrowly obovate to oblanceolate-falcate, 25–40 mm;

styles (4–)5, 3–7 mm.

Capsules

ovoid, 12–20(–30) × 10–13 mm.

Seeds

1.5 mm, narrowly winged;

testa shallowly linear-reticulate.

Hypericum ascyron subsp. pyramidatum

Hypericum ascyron

Phenology Flowering summer (Jun–Aug).
Habitat Stream sides, roadside ditches, fens, damp meadows
Elevation 0–1500 m (0–4900 ft)
Distribution
from FNA
CT; IA; IL; IN; KS; MA; MD; MI; MN; MO; NY; OH; PA; VT; WI; ON; QC
from FNA
CT; IA; IL; IN; KS; MA; MD; MI; MN; MO; NY; OH; PA; VT; WI; ON; QC; Asia (e China, Japan, Korea, Siberia)
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Discussion

The American populations of Hypericum ascyron sometimes have been treated as distinct from those of eastern Asia, usually as H. pyramidatum. These populations can be distinguished by the combination of relatively broad leaves, acute sepals, and, usually, almost distinct styles; they are better treated as subsp. pyramidatum (see N. K. B. Robson 2001). The scattered American distribution of Hypericum ascyron, which seems to coincide well with earlier Native American campsites, led W. G. Dore (in herbarium notes) to suggest that it was distributed by aborigines for an as yet unknown reason (see J. M. Gillett and N. K. B. Robson 1981).

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

Subspecies 3 (1 in the flora).

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

Source FNA vol. 6, p. 97. FNA vol. 6, p. 97.
Parent taxa Hypericaceae > Hypericum > sect. Roscyna > Hypericum ascyron Hypericaceae > Hypericum > sect. Roscyna
Sibling taxa
H. adpressum, H. anagalloides, H. apocynifolium, 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. sphaerocarpum, H. suffruticosum, H. tenuifolium, H. tetrapetalum, H. virgatum, H. ×mitchellianum
Subordinate taxa
H. ascyron subsp. pyramidatum
Synonyms H. pyramidatum, H. ascyroides, H. ascyron var. americanum, H. bartramium, H. macrocarpum, Roscyna americana
Name authority (Aiton) N. Robson: Bull. Nat. Hist. Mus. London, Bot. 31: 58. (2001) Linnaeus: Sp. Pl. 2: 783. (1753)
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