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Photo is of parent taxon

dwarf St. John's-wort, small Canadian St. John's-wort, small flower st john's wort

Habit Herbs annual or perennial, usually erect, sometimes decumbent and rooting, basal branches sometimes present, usually with to 10 pairs of spreading branches distal to middle, 0.5–8 dm.
Stems

apical internode usually longer than adjacent one.

internodes 4-angled.

Leaves

blades broadly ovate or broadly oblong-ovate to suborbiculate.

spreading, sessile or amplexicaul;

blade paler abaxially, ovate, elliptic, or elliptic-oblong (proximal), ovate or suborbiculate to elliptic or lanceolate (mid and distal), 3–27(–40) × 1–15 mm, papery to membranous, margins plane, apex obtuse to rounded, basal veins 3–5, midrib with to 3 pairs of branches.

Inflorescences

branching from 1–4(–6) nodes, branches diffuse and repeatedly monochasial distally.

cylindric, 5–60-flowered, branching mostly dichasial;

bracts linear-subulate.

Flowers

3–5 mm diam.;

sepals lanceolate to linear-lanceolate or elliptic-oblong to oblanceolate, equal or unequal, 2–4.5 × 0.6–1.5 mm, margins sometimes ciliate, not setulose-ciliate, apex usually acute to apiculate, sometimes obtuse to rounded;

petals pale yellow, oblong, 1.7–3.5 mm;

stamens 5–16, scarcely grouped;

styles 0.5 mm;

stigmas broadly capitate.

Capsules

narrowly ovoid to cylindric-ellipsoid, 2–5 × 1.6–2.4 mm, usually broadest at or near middle.

Seeds

0.4–0.7 mm;

testa finely linear-scalariform.

Sepals

± imbricate, broader beyond middle.

Hypericum mutilum subsp. latisepalum

Hypericum mutilum

Phenology Flowering late spring–early summer (Apr–Jun).
Habitat Ditches, marshes, lake margins, desiccated temporary pools
Elevation 0–200 m (0–700 ft)
Distribution
from FNA
FL; GA; NJ; SC; TX
from FNA
AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MS; NC; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; VT; WA; WI; WV; BC; NB; NS; ON; QC; SK [Introduced in w North America]
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[BONAP county map]
Discussion

Fernald recorded subsp. latisepalum from New Jersey; D. H. Webb (1980) did not record it north of South Carolina. No specimens have been seen from farther north than Georgia, where it appears to tend morphologically toward subsp. mutilum.

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

Subspecies 2 (2 in the flora).

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

Key
1. Stems: apical internode shorter than adjacent one or almost absent; inflorescences: branching mostly dichasial from 2–10 nodes.
subsp. mutilum
1. Stems: apical internode usually longer than adjacent one; inflorescences: branching from 1–4(–6) nodes, branches diffuse and repeatedly monochasial distally.
subsp. latisepalum
Source FNA vol. 6, p. 94. FNA vol. 6, p. 93.
Parent taxa Hypericaceae > Hypericum > sect. Brathys > Hypericum mutilum Hypericaceae > Hypericum > sect. Brathys
Sibling taxa
H. mutilum subsp. mutilum
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. 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. mutilum subsp. latisepalum, H. mutilum subsp. mutilum
Synonyms H. mutilum var. latisepalum Sarothra mutila
Name authority (Fernald) N. Robson: Bull. Brit. Mus. (Nat. Hist.), Bot. 20: 119. (1990) Linnaeus: Sp. Pl. 2: 787. (1753)
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