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

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

Canadian St. John's-wort, lesser Canadian St. John's wort, lesser St. John's-wort, millepertuis de Canada

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. Herbs annual or perennial, erect, basal branches relatively few or none, usually with strict, ascending branches from distal nodes, 0.3–7.5 dm.
Stems

internodes 4-angled.

internodes 4-angled.

Leaves

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.

erect or spreading, sessile or subsessile;

blade linear to oblanceolate-linear or (proximal) oblanceolate to obovate, 6–55 × 0.5–5.5 mm, papery to membranous, margins plane, apex rounded, basal or near-basal veins 1–3(–5), midrib with 1–4 pairs of branches.

Inflorescences

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

bracts linear-subulate.

corymbiform to cylindric, usually diffuse, 1–35-flowered, branching mostly dichasial.

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.

5–6 mm diam.;

sepals linear-lanceolate to lanceolate, equal, 2.5–4.5 × 0.8–1 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to acuminate;

petals golden yellow, sometimes red-veined, narrowly obovate to elliptic, 2.5–4 mm;

stamens 12–25, obscurely 3–5-fascicled;

styles 0.5–0.8 mm;

stigmas broadly capitate.

Capsules

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

narrowly conic to conic-cylindric, 4–6 × 1.5–3 mm, broadest proximal to middle.

Seeds

0.4–0.7 mm;

testa finely linear-scalariform.

0.5–0.7 mm;

testa finely linear-scalariform.

2n

= 16.

Hypericum mutilum

Hypericum canadense

Phenology Flowering summer (Jun–Sep).
Habitat Fens, marshes, depressions, lake and pond margins
Elevation 0–500 m (0–1600 ft)
Distribution
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]
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DC; DE; FL; GA; IA; IL; IN; KY; MA; MD; ME; MI; MN; MS; NC; NH; NJ; NY; OH; OR; PA; RI; SC; TN; VA; VT; WA; WI; WV; NB; NF; NS; ON; PE; QC; SPM [Introduced in Europe (Ireland, The Netherlands)]
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

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

Hypericum canadense is closely related to H. majus; it hybridizes with that species and with H. mutilum, producing intermediate forms. Hypericum ×dissimulatum E. P. Bicknell appears to comprise a continuous series of hybrids between H. canadense and

H. mutilum or H. boreale such that it is not always possible to say which of these species is involved. Hypericum ×dissimulatum has been recorded from New Brunswick, Newfoundland, Nova Scotia, Ontario, and Quebec and from Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, and Virginia.

J. Rousseau reduced Hypericum canadense var. minimum to a form; it does not seem to merit any recognition.

(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. 93. FNA vol. 6, p. 92.
Parent taxa Hypericaceae > Hypericum > sect. Brathys 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. 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. 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. mutilum subsp. latisepalum, H. mutilum subsp. mutilum
Synonyms Sarothra mutila Brathys canadensis, H. canadense var. galiiforme, H. canadense var. magninsulare, H. canadense var. minimum
Name authority Linnaeus: Sp. Pl. 2: 787. (1753) Linnaeus: Sp. Pl. 2: 785. (1753)
Web links