Flora of North America species comparison

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Hypericum sect. Myriandra

Hypericum kalmianum

Kalm's St. John's-wort, millepertuis de Kalm
Habit Herbs (perennial), subshrubs, or shrubs; black glands absent. Shrubs, erect, forming slender to rounded or flat-topped bush, (1.4–)2–6(–10) dm.
Stems

internodes 4-lined at first, then terete.
Leaves

deciduous (base articulated) or persistent (base not articulated).

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

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

7–45 mm diam.;

sepals deciduous or persistent, (2–)4–5;

petals deciduous, (3–)4–5;

stamens usually persistent, sometimes deciduous, 30–650, in continuous ring or in 4–5 barely discernable fascicles, each of 1–2 stamens;

ovary 2–5-merous;

placentation incompletely axile to parietal;

styles ± appressed, bases distinct;

stigmas minute.

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

narrowly ovoid-conic, 7–11 × 4–7 mm.
Seeds

± carinate or not.

narrowly carinate, 0.7–1.1 mm;

testa subscalariform.
2n

= 18.

Hypericum sect. Myriandra

Hypericum kalmianum
Phenology Flowering summer (Jul–Aug).
Habitat Sandy or calcareous dune slacks or swales, rocky shores, plains and low prairies, along streams, sphagnum-sedge swamps
Elevation 10–400 m (0–1300 ft)
Distribution
e North America; e Mexico; West Indies (Bahamas, Greater Antilles); Bermuda; Central America (Belize)
from FNA
IL; IN; MI; NY; OH; WI; ON; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Species 29 (28 in the flora).

Hypericum limosum Grisebach is endemic to western Cuba.

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

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.)
Key
1. Sepals enclosing capsule, (2–)4, unequal (outer pair larger) [subsect. Ascyrum]
→ 2
1. Sepals not enclosing capsule, usually 5, if 3 or 4, usually subequal
→ 6
2. Stamens 30–50; ovaries 2-merous
→ 3
2. Stamens 70–100; ovaries 3(4)-merous
→ 4
3. Leaf bases without glandlike auricles; inflorescences 1-flowered, pedicels mostly recurved to reflexed in fruit, bracteoles proximal.
H. suffruticosum
3. Leaf bases with glandlike auricles; inflorescences 1–12-flowered, pedicels erect in fruit, bracteoles distal.
H. hypericoides
4. Leaf bases cordate-amplexicaul; inflorescences terminal, branching (at apical node) pseudodichotomous
H. tetrapetalum
4. Leaf bases usually cuneate to subrounded, rarely rounded to slightly subcordate-amplexicaul; inflorescences from 1–4 nodes, branching dichasial or pseudodichotomous
→ 5
5. Leaves: bases without glandlike auricles, margins plane to subrecurved; inflorescences 1–3(–7)-flowered, branching dichasial; outer sepals: apices apiculate or obtuse to rounded
H. crux-andreae
5. Leaves: bases with glandlike auricles, margins subrecurved to subincrassate; inflorescences 1-flowered, branching pseudodichotomous; outer sepals: apices acute to subacuminate
H. edisonianum
6. Leaves: bases usually not articulated, if articulated (22. H. myrtifolium), subcordate-amplexicaul; stamens (all or some) usually persistent (deciduous in H. apocynifolium, H. myrtifolium, and H. dolabriforme)
→ 7
6. Leaves: base articulated, not amplexicaul; stamens deciduous [subsect. Centrosperma]
→ 16
7. Shrubs, decumbent, mat-forming, wiry; inflorescences 1(–5)-flowered [subsect. Pseudobrathydium].
H. buckleyi
7. Herbs, subshrubs, or shrubs, erect to ascending or decumbent, not mat-forming, not wiry; inflorescences (1–)3–70-flowered
→ 8
8. Inflorescences widely branched; stamens 120–200 [subsect. Brathydium]
→ 9
8. Inflorescences narrowly branched; stamens 30–95 [subsect. Suturosperma]
→ 10
9. Shrubs, erect, unbranched or branched distally, bark corky; leaf blades oblong-ovate to triangular-lanceolate, (5–)7–20 mm wide, bases articulated, subcordate-amplexicaul.
H. myrtifolium
9. Subshrubs, decumbent, ± branching, bark not corky (thin); leaf blades linear-elliptic or linear-oblong to linear, 3–5 mm wide, bases not articulated, narrowly cuneate to rounded.
H. dolabriforme
10. Leaf blades (7–)10–25 mm wide; sepals deciduous or tardily deciduous; placentation incompletely axile
→ 11
10. Leaf blades 1–10(–15) mm wide; sepals persistent; placentation parietal
→ 12
11. Inflorescences terminal, (1–)3–5(–8)-flowered; sepals tardily deciduous, 1.5–2.3 mm wide; capsules 6–15 × 4.5–8 mm.
H. apocynifolium
11. Inflorescences from 1–3 nodes, the terminal 7–45-flowered; sepals deciduous, 1–1.5 mm wide; capsules 3.5–7 × 3–5 mm.
H. nudiflorum
12. Shrubs; leaf blades 1–3 mm wide; inflorescences 1–3-flowered; sepals (3–)4(–5).
H. microsepalum
12. Herbs, subshrubs, or shrubs; leaf blades (1–)3–15 mm wide; inflorescences usually 7–70-flowered, if flowers 1–6, herbs; sepals usually 5
→ 13
13. Shrubs; capsules ovoid-cylindric to broadly ovoid.
H. cistifolium
13. Herbs or subshrubs; capsules usually broadly ovoid to depressed-globose, if ovoid-ellipsoid to ellipsoid or globose, rhizomatous herbs
→ 14
14. Herbs or subshrubs, not or rarely rhizomatous; capsules broadly ovoid to depressed-globose; seeds 2–2.7 mm.
H. sphaerocarpum
14. Herbs, rhizomatous; capsules ellipsoid to ovoid-ellipsoid or globose; seeds 0.6–0.7 mm
→ 15
15. Herbs, 2–8 dm, relatively stout; leaf blades narrowly oblong or linear to lanceolate or narrowly elliptic.
H. adpressum
15. Herbs, 1–3(–5) dm, relatively slender; leaf blades elliptic or oblanceolate to oblong-elliptic.
H. ellipticum
16. Leaf blades usually elliptic, lanceolate, linear, oblanceolate, or oblong, (1–)3–22 mm wide; sepals usually elliptic, linear, oblanceolate, oblong, obovate, ovate, or spatulate
→ 17
17. Inflorescences usually 1–3(–7+)-flowered from apical node, sometimes with single flowers at 1(–2) proximal nodes
→ 18
17. Inflorescences usually (1–)3–25-flowered from apical node, sometimes with triads, dichasia, or flowering branches from 1–4 proximal nodes
→ 19
18. Shrubs (6–)10–30 dm; leaf blades 8–22 mm wide, margins plane or subrecurved; sepals 4–10 mm wide; ovaries 3-merous.
H. frondosum
18. Shrubs (1.4–)2–6(–10) dm; leaf blades 3–7(–10) mm wide, margins subrecurved to revolute; sepals 1.5–5 mm wide; ovaries (3–)5(–6)-merous.
H. kalmianum
19. Stem internodes 4- or 6-lined at first; inflorescences cylindric or broadly to narrowly elongate-cylindric with 1–5(–7)-flowered lateral dichasia proximally; internodes 4-lined at first and capsules 7–13 mm or internodes 6-lined at first and capsules 4.5–6 mm
→ 20
19. Stem internodes 4-lined at first; inflorescences shortly and broadly pyramidal or broadly cylindric to globose-cylindric, or obpyramidal with (2–)5–15-flowered lateral dichasia proximally; capsules 5–7 mm
→ 21
20. Leaf blades 30–70 mm, narrowly oblong to narrowly elliptic-oblanceolate; flowers 15–30 mm diam.; placentation incompletely axile; capsules 7–13 mm; seeds 1.5–2 mm.
H. prolificum
20. Leaf blades 15–32(–37) mm, narrowly oblong-elliptic or oblanceolate to linear; flowers 9–14 mm diam.; placentation parietal; capsules 4.5–6 mm; seeds 0.7–0.8 mm.
H. galioides
21. Sepals: basal veins 3–7; ovaries (3–)4–5-merous; capsules notably lobed.
H. lobocarpum
21. Sepals: basal veins 1–3; ovaries 3–4(–5)-merous; capsules not or scarcely lobed.
H. densiflorum
22. Shrubs, erect, 3–45 dm
→ 24
23. Leaf blades 13–25 mm; sepals (3–)4.5–7 mm.
H. lloydii
23. Leaf blades 4–11 mm; sepals 2–4 mm.
H. tenuifolium
24. Capsules usually cylindric, rarely narrowly conic or ovoid-conic; bark smooth, not metallic-silvery
→ 25
24. Capsules ± narrowly ovoid-conic or pyramidal-ovoid to ovoid or ellipsoid; bark smooth and metallic-silvery or corky to spongy
→ 26
25. Leaves 9–26 mm; styles shorter than ovaries; capsules (4.5–)5–7 mm.
H. nitidum
25. Leaves 6–12 mm; styles longer than ovaries; capsules 3.5–5 mm.
H. brachyphyllum
26. Bark smooth and metallic-silvery, exfoliating in thin, curled plates; styles 5 mm; seeds 1–1.6 mm; young stems, leaves, and sepals glaucous.
H. lissophloeus
26. Bark corky to spongy, exfoliating in thin, papery sheets or plates; styles 2.5–4 mm; seeds 0.4–0.8 mm; young stems, leaves, and sepals not glaucous
→ 27
27. Stems: internodes 6-lined at first, soon 2-winged, then terete; bark smooth; terminal inflorescence (3–)7–32-flowered.
H. fasciculatum
27. Stems: internodes 4-lined at first, soon 4-angled, then terete; bark striate; terminal inflorescence 1–3-flowered.
H. chapmanii
Source FNA vol. 6, p. 74. FNA vol. 6, p. 77.
Parent taxa Hypericaceae > Hypericum 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. 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. adpressum, H. apocynifolium, H. brachyphyllum, H. buckleyi, H. chapmanii, H. cistifolium, H. crux-andreae, H. densiflorum, H. dolabriforme, H. edisonianum, H. ellipticum, H. fasciculatum, H. frondosum, H. galioides, H. hypericoides, H. kalmianum, H. lissophloeus, H. lloydii, H. lobocarpum, H. microsepalum, H. myrtifolium, H. nitidum, H. nudiflorum, H. prolificum, H. sphaerocarpum, H. suffruticosum, H. tenuifolium, H. tetrapetalum
Synonyms section Myriandra Norysca kalmiana
Name authority (Spach) R. Keller: in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 95[III,6]: 214. (1893) Linnaeus: Sp. Pl. 2: 783. (1753)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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