Hypericum perforatum
Hypericum frondosum
Chase-devil, common St. John's-wort, Klamath weed, millepertuis commun, Tipton's weed
cedar glade St. John's-wort, golden St. John's wort
internodes 4-lined at first, then 2-lined to terete.
blades usually oblong to lanceolate-oblong, sometimes oblanceolate, 25–65 × 8–22 mm, base articulated, broadly to narrowly cuneate, margins plane or subrecurved, apex apiculate-obtuse to rounded, midrib with 10–16 pairs of branches.
1–3(–7)-flowered from apical node, sometimes with paired single flowers or triads (3-flowered cymules) or 1–3-flowered branches at proximal node.
24–45 mm diam.;
sepals deciduous, not enclosing capsule, (4)5, ovate or oblong to elliptic-spatulate, unequal, 6–14(–20) × 4–10 mm;
petals (4–)5, golden yellow to orange-yellow, obovate to oblanceolate, 12–25 mm;
stamens deciduous, 250–650;
ovary 3-merous.
ovoid-conic to ovoid-rostrate, 12–15 × 6–8 mm.
carinate, 1.5 mm;
testa linear-reticulate.
= 18.
Hypericum perforatum
Hypericum frondosum
Subspecies 4 (1 in the flora).
Hypericum perforatum has been introduced into various parts of the world, including North America, where only subsp. perforatum is represented. The range of variation in the flora area is less than occurs in Europe, and signs of hybridization that are common there are absent in North America.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Hypericum frondosum is endemic to the southwestern end of the Appalachian Range; it is recorded as introduced in Connecticut, Massachusetts, and New York (W. P. Adams 1962). Records from Arkansas and, possibly, South Carolina and Virginia appear to be errors for H. prolificum. Although H. frondosum is variable over its natural range and approaches H. prolificum morphologically in Arkansas, it remains distinct from its immediate relatives. In cultivation, it sometimes hybridizes with H. prolificum. Artificial hybrids have been made, as well as artificial tetraploids (O. Myers 1963).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
OR, 
WA - Local Web sites:
CalFlora, CalPhotos, 
Flora NW, 
Go Botany, 
IL Wildflowers, 
KS Wildflowers, 
MD Biodiversity, 
MI Flora, 
MN Wildflowers, 
MO Plants, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
LA Plants
