1	Sepals enclosing capsule, (2–)4, unequal (outer pair larger) [subsect. Ascyrum]		(2)
+	Sepals not enclosing capsule, usually 5, if 3 or 4, usually subequal		(6)
2 (1)	Stamens 30–50; ovaries 2-merous		(3)
+	Stamens 70–100; ovaries 3(4)-merous		(4)
3 (2)	Leaf bases without glandlike auricles; inflorescences 1-flowered, pedicels mostly recurved to reflexed in fruit, bracteoles proximal.		27 Hypericum suffruticosum
+	Leaf bases with glandlike auricles; inflorescences 1–12-flowered, pedicels erect in fruit, bracteoles distal.		28 Hypericum hypericoides
4 (2)	Leaf bases cordate-amplexicaul; inflorescences terminal, branching (at apical node) pseudodichotomous		25. Hypericum tetrapetalum
+	Leaf bases usually cuneate to subrounded, rarely rounded to slightly subcordate-amplexicaul; inflorescences from 1–4 nodes, branching dichasial or pseudodichotomous		(5)
5 (4)	Leaves: bases without glandlike auricles, margins plane to subrecurved; inflorescences 1–3(–7)-flowered, branching dichasial; outer sepals: apices apiculate or obtuse to rounded		24. Hypericum crux-andreae
+	Leaves: bases with glandlike auricles, margins subrecurved to subincrassate; inflorescences 1-flowered, branching pseudodichotomous; outer sepals: apices acute to subacuminate		26. Hypericum edisonianum
6 (1)	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)
+	Leaves: base articulated, not amplexicaul; stamens deciduous [subsect. Centrosperma]		(16)
7	Shrubs, decumbent, mat-forming, wiry; inflorescences 1(–5)-flowered [subsect. Pseudobrathydium].		14 Hypericum buckleyi
+	Herbs, subshrubs, or shrubs, erect to ascending or decumbent, not mat-forming, not wiry; inflorescences (1–)3–70-flowered		(8)
8 (7)	Inflorescences widely branched; stamens 120–200 [subsect. Brathydium]		(9)
+	Inflorescences narrowly branched; stamens 30–95 [subsect. Suturosperma]		(10)
9 (8)	Shrubs, erect, unbranched or branched distally, bark corky; leaf blades oblong-ovate to triangular-lanceolate, (5–)7–20 mm wide, bases articulated, subcordate-amplexicaul.		22 Hypericum myrtifolium
+	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.		23 Hypericum dolabriforme
10 (8)	Leaf blades (7–)10–25 mm wide; sepals deciduous or tardily deciduous; placentation incompletely axile		(11)
+	Leaf blades 1–10(–15) mm wide; sepals persistent; placentation parietal		(12)
11 (10)	Inflorescences terminal, (1–)3–5(–8)-flowered; sepals tardily deciduous, 1.5–2.3 mm wide; capsules 6–15 × 4.5–8 mm.		15 Hypericum apocynifolium
+	Inflorescences from 1–3 nodes, the terminal 7–45-flowered; sepals deciduous, 1–1.5 mm wide; capsules 3.5–7 × 3–5 mm.		16 Hypericum nudiflorum
12 (10)	Shrubs; leaf blades 1–3 mm wide; inflorescences 1–3-flowered; sepals (3–)4(–5).		18 Hypericum microsepalum
+	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 (12)	Shrubs; capsules ovoid-cylindric to broadly ovoid.		17 Hypericum cistifolium
+	Herbs or subshrubs; capsules usually broadly ovoid to depressed-globose, if ovoid-ellipsoid to ellipsoid or globose, rhizomatous herbs		(14)
14 (13)	Herbs or subshrubs, not or rarely rhizomatous; capsules broadly ovoid to depressed-globose; seeds 2–2.7 mm.		19 Hypericum sphaerocarpum
+	Herbs, rhizomatous; capsules ellipsoid to ovoid-ellipsoid or globose; seeds 0.6–0.7 mm		(15)
15 (14)	Herbs, 2–8 dm, relatively stout; leaf blades narrowly oblong or linear to lanceolate or narrowly elliptic.		20 Hypericum adpressum
+	Herbs, 1–3(–5) dm, relatively slender; leaf blades elliptic or oblanceolate to oblong-elliptic.		21 Hypericum ellipticum
16 (6)	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 (16)	Inflorescences usually 1–3(–7+)-flowered from apical node, sometimes with single flowers at 1(–2) proximal nodes		(18)
+	Inflorescences usually (1–)3–25-flowered from apical node, sometimes with triads, dichasia, or flowering branches from 1–4 proximal nodes		(19)
18 (17)	Shrubs (6–)10–30 dm; leaf blades 8–22 mm wide, margins plane or subrecurved; sepals 4–10 mm wide; ovaries 3-merous.		1 Hypericum frondosum
+	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.		3 Hypericum kalmianum
19 (17)	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)
+	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 (19)	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.		2 Hypericum prolificum
+	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.		6 Hypericum galioides
21 (19)	Sepals: basal veins 3–7; ovaries (3–)4–5-merous; capsules notably lobed.		4 Hypericum lobocarpum
+	Sepals: basal veins 1–3; ovaries 3–4(–5)-merous; capsules not or scarcely lobed.		5 Hypericum densiflorum
22	Shrubs, erect, 3–45 dm		(24)
23	Leaf blades 13–25 mm; sepals (3–)4.5–7 mm.		7 Hypericum lloydii
+	Leaf blades 4–11 mm; sepals 2–4 mm.		8 Hypericum tenuifolium
24 (22)	Capsules usually cylindric, rarely narrowly conic or ovoid-conic; bark smooth, not metallic-silvery		(25)
+	Capsules ± narrowly ovoid-conic or pyramidal-ovoid to ovoid or ellipsoid; bark smooth and metallic-silvery or corky to spongy		(26)
25 (24)	Leaves 9–26 mm; styles shorter than ovaries; capsules (4.5–)5–7 mm.		9 Hypericum nitidum
+	Leaves 6–12 mm; styles longer than ovaries; capsules 3.5–5 mm.		10 Hypericum brachyphyllum
26 (24)	Bark smooth and metallic-silvery, exfoliating in thin, curled plates; styles 5 mm; seeds 1–1.6 mm; young stems, leaves, and sepals glaucous.		11 Hypericum lissophloeus
+	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 (26)	Stems: internodes 6-lined at first, soon 2-winged, then terete; bark smooth; terminal inflorescence (3–)7–32-flowered.		12 Hypericum fasciculatum
+	Stems: internodes 4-lined at first, soon 4-angled, then terete; bark striate; terminal inflorescence 1–3-flowered.		13 Hypericum chapmanii