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round-fruit St. John's-wort, roundseed St. Johnswort

St. Andrew's cross

Habit Herbs (perennial) or subshrubs, erect or decumbent, not or rarely rhizomatous, unbranched or branched proximally, 2–6 dm. Subshrubs or shrubs, erect or decumbent to prostrate, unbranched or branched, sometimes diffuse and mat-forming, 0.5–3 or 3–15 dm.
Stems

internodes 2–4-lined.

internodes 2-winged.

Leaf

blades narrowly elliptic or narrowly oblong to linear, 30–70 × 3–15 mm, base not articulated, narrowly cuneate to linear, margins plane to revolute, apex subacute to rounded, midrib with 0–4 pairs of branches.

blades oblanceolate or narrowly oblong or elliptic to linear, 7–25 × 1–8.5 mm, base not articulated, usually cuneate, sometimes rounded, with glandlike auricles, margins subrecurved, apex rounded to obtuse, midrib with 1–2 pairs of branches.

Inflorescences

rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes.

narrowly cylindric to pyramidal, 1–12-flowered from 1–4 nodes, sometimes with branches from to 10 proximal nodes, or branching more elaborate and pseudodichotomous;

pedicels erect in fruit, bracteoles distal.

Flowers

10–15 mm diam.;

sepals persistent, not enclosing capsule, 5, broadly ovate to oblong-elliptic, ± unequal, 2.5–5 × 1.5–3 mm;

petals 5, bright yellow, oblanceolate-elliptic to elliptic, 5–9 mm;

stamens persistent, 45–85;

ovary 3-merous, placentation parietal.

10–20 mm diam.;

sepals persistent, enclosing capsule, 4, unequal, outer ovate-suborbiculate to narrowly elliptic, 5–12.5 × 2–13 mm, apex subapiculate to obtuse, inner lanceolate, 1–4 × 2 mm, apex acute;

petals 4, bright to pale yellow, obovate to narrowly oblong-elliptic, 6–12 mm;

stamens persistent, 40–50;

ovary 2-merous.

Capsules

broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm.

narrowly compressed-ovoid to cylindric-ellipsoid, 5–9 × 2–4 mm.

Seeds

carinate, 2–2.7 mm;

testa coarsely reticulate.

not carinate, 0.6–0.8 mm;

testa finely linear-reticulate to linear-foveolate.

Hypericum sphaerocarpum

Hypericum hypericoides

Phenology Flowering summer (Jun–Aug).
Habitat Rocky outcrops or embankments, prairies, stream banks, usually wet or moist, railroad embankments
Elevation 500–1000 m (1600–3300 ft)
Distribution
from FNA
AL; AR; IA; IL; IN; KS; KY; MI; MO; MS; NE; OH; OK; TN; TX; WI; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; DC; DE; FL; GA; IL; IN; KS; KY; LA; MA; MD; MO; MS; NC; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV; Mexico; West Indies (Bahamas, Greater Antilles); Bermuda; Central America (Guatemala, Honduras)
[WildflowerSearch map]
[BONAP county map]
Discussion

Hypericum sphaerocarpum differs from H. cistifolium and H. nudiflorum in its semiherbaceous habit and more northwestern distribution, as well as in its combination of relatively long, narrow leaves, persistent sepals, globose and apiculate to rounded capsules, and relatively large seeds. The narrow-leaved, bushy form from eastern parts of the range (var. turgidum) merges with the typical form.

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

Subspecies 3 (2 in the flora).

Hypericum hypericoides can be distinguished from H. crux-andreae by the two-merous ovary, narrower leaves, smaller flowers, and more richly-branched stems. It is variable in leaf and sepal shape and size; three subspecies can be recognized.

The erect bushy form (subsp. hypericoides) is most widespread and has given rise to a northern diffuse form (subsp. multicaule) in the United States and a prostrate form (subsp. prostratum N. Robson) in Hispaniola.

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

Key
1. Plants erect, usually unbranched from base and freely branched well above ground level; leaf blades usually narrowly elliptic to narrowly oblong, broadest near middle.
subsp. hypericoides
1. Plants decumbent to prostrate, branching from base; leaf blades usually oblanceolate, broadest beyond middle.
subsp. multicaule
Source FNA vol. 6, p. 83. FNA vol. 6, p. 87.
Parent taxa Hypericaceae > Hypericum > sect. Myriandra 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. 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. suffruticosum, H. tenuifolium, H. tetrapetalum, H. virgatum, H. ×mitchellianum
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. 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. hypericoides subsp. hypericoides, H. hypericoides subsp. multicaule
Synonyms Brathydium chamaenerium, B. sphaerocarpum, H. chamaenerium, H. sphaerocarpum var. turgidum, H. turgidum Ascyrum hypericoides
Name authority Michaux: Fl. Bor.-Amer. 2: 78. (1803) (Linnaeus) Crantz: Inst. Rei Herb. 2: 520. (1766)
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