Hypericum densiflorum

Pursh

Fl. Amer. Sept. 2: 376. 1813.

Common names: Bushy St. John’s wort
Endemic
Synonyms: Hypericum glomeratum Small H. interior Small H. nothum Rehder H. prolificum var. densiflorum (Pursh) A. Gray
Treatment appears in FNA Volume 6. Treatment on page 78. Mentioned on page 75, 76.

Shrubs, erect, forming slender bush, 6–30 dm. Stems: internodes 4-lined at first, soon 2-lined to terete. Leaf-blades narrowly elliptic-oblong or oblanceolate to linear, 20–45 × 2–7 mm, base articulated, narrowly cuneate to attenuate, margins recurved to revolute, apex apiculate-rounded to subacute, midrib with 14–17 pairs of branches. Inflorescences broadly pyramidal to broadly cylindric, 5–25-flowered from apical node, with (2–) 5–15-flowered dichasia from 1–2 proximal nodes. Flowers 10–17 (–20) mm diam.; sepals deciduous, not enclosing capsule, 5, narrowly oblong to oblanceolate-spatulate, unequal or subequal, 4–6 × 1–1.5 mm, basal veins 1–3; petals 5, deep golden yellow, obovate-oblanceolate, 6–9 mm; stamens deciduous, 100–150; ovary 3–4 (–5) -merous. Capsules narrowly ovoid conic to cylindric-ovoid, 5–6 (–7) × 2–3 mm, not or scarcely lobed. Seeds not carinate, 0.8–1.3 mm; testa linear-reticulate. 2n = 18.


Phenology: Flowering summer (Jun–Aug).
Habitat: Wet or moist habitats (meadows, lake margins, pinelands, etc.), road embankments, rocky hillsides
Elevation: 0–1000 m

Distribution

V6 120-distribution-map.jpg

Ala., Del., Ga., Ky., Md., N.J., N.C., Pa., S.C., Tenn., Va., W.Va.

Discussion

Hybrid intermediates between Hypericum densiflorum and H. lobocarpum occur in northwestern Alabama, and a narrow-leaved, small-flowered form in Tennessee and northern Georgia (H. interior) verges toward H. galioides. Hypericum densiflorum is always distinct from H. prolificum in the wild; these species hybridize in gardens. Hypericum ×arnoldianum Rehder, known in cultivation only, was thought by Rehder to have the parentage H. galioides × lobocarpum; on both morphological and cytological grounds, the conclusion of W. P. Adams (1972) that it was H. densiflorum × lobocarpum seems much more likely.

Selected References

None.

Lower Taxa

None.
... more about "Hypericum densiflorum"
reddish +  and black +
yellow;orange +
oblong;ellipsoid +
apiculate-rounded;subacute +
Norman K. B. Robson +
striate +  and smooth +
punctiform +
articulated +
distinct +
narrowly cuneate +  and attenuate +
Undefined sect. Myriandra +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
lobed;conic;cylindric-ovoid +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Bushy St. John’s wort +
(2-)5-15-flowered +
Ala. +, Del. +, Ga. +, Ky. +, Md. +, N.J. +, N.C. +, Pa. +, S.C. +, Tenn. +, Va. +  and W.Va. +
0–1000 m +
connate +  and distinct +
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
Wet or moist habitats (meadows, lake margins, pinelands, etc.), road embankments, rocky hillsides +
axillary +  and terminal +
broadly pyramidal +  and broadly cylindric +
2-lined +  and 4-lined +
2 cm20 mm <br />0.02 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
oblanceolate;linear +
glanduliferous +, petiolate +, pseudopetiolate +, subsessile +, sessile +, estipulate +  and simple +
persistent +  and deciduous +
glandular-ciliate +
3-4(-5)-merous +
incompletely axile +  and parietal +
glanduliferous +
contorted +  and imbricate +
golden yellow +
deciduous +
distinct +
obovate-oblanceolate +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
Flowering summer (Jun–Aug). +
Fl. Amer. Sept. +
not carinate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (?) +  and 0.13 cm1.3 mm <br />0.0013 m <br /> (?) +
deciduous +
connate +  and distinct +
narrowly oblong;oblanceolate-spatulate +
subequal +  and unequal +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
connate +  and distinct +
spreading;more or less appressed +
elongate +
Hypericum glomeratum +, H. interior +, H. nothum +  and H. prolificum var. densiflorum +
Hypericum densiflorum +
Hypericum sect. Myriandra +
species +
scalariform +
reticulate +  and foveolate +
perennial +  and annual +
shrub +  and bush +
hairy +  and glabrous +
6 +, 9 +  and 7 +