Hypericum gymnanthum
claspingleaf St. Johnswort, small-flower St. John's wort
internodes 4-angled.
spreading, sessile or amplexicaul;
blade usually ovate-triangular to broadly ovate, rarely oblong (mid and distal blades lanceolate-deltate), 5–25 × 3–12 mm, papery to membranous, margins plane, apex usually subacute, basal veins (3–)5, midrib usually with 1–2 pairs of branches.
laxly corymbiform to cylindric, (1–)5–65-flowered, branching mostly dichasial.
4.5–7 mm diam.;
sepals lanceolate to narrowly ovate, equal, 3–5 × 0.8–1.2 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to acuminate;
petals bright yellow, oblanceolate, 2–4 mm;
stamens 10–14, scarcely grouped;
styles 0.5–0.7 mm;
stigmas broadly capitate.
narrowly conic-ellipsoid, 3–5 × 1.5–2 mm, usually broadest at or near middle.
0.5–0.6 mm;
testa finely linear-scalariform.
= 16.
Hypericum gymnanthum
Hypericum gymnanthum was introduced into Poland; it is now extinct there. It is closely related to H. mutilum; it differs from that species in the broader, usually deltate leaves; fewer, stricter branches; no condensed apical stem internode; and larger flowers with lanceolate to ovate sepals.
Hybrids of Hypericum gymnanthum with H. mutilum have been reported from Maryland, Mississippi, North Carolina, Tennessee, and West Virginia, and, perhaps erroneously, with H. canadense from Virginia.
Hypericum gymnanthum has clearly been introduced (recently?) into the Azores, not necessarily by man. Seeds may well have been carried there by birds.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
LA Plants
MD Biodiversity
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
