Hypericum sphaerocarpum
Hypericum boreale
round-fruit St. John's-wort, roundseed St. Johnswort
millepertuis bor é al, northern bog St. John's-wort, northern St. John's-wort
internodes 2–4-lined.
internodes 4-angled, apical internode shorter than adjacent one or almost absent.
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.
spreading, sessile;
blade (concolor), broadly to narrowly oblong or elliptic to oblanceolate or round, 5–15 × 2–5 mm, papery to membranous, margins plane, apex rounded, basal veins 3–5, midrib branched or not.
rounded-corymbiform, 7–70-flowered, narrowly branched, sometimes with dichasia or branches from to 8 proximal nodes.
cylindric to rounded-pyramidal, 1–13-flowered, branching mostly dichasial;
bracts not linear-subulate.
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.
3–5 mm diam.;
sepals usually lanceolate to narrowly oblong, rarely oblanceolate, equal, 2.5 × 0.8–1 mm, margins sometimes ciliate, not setulose-ciliate, apex rounded;
petals pale yellow, oblong, 1.7–3.5 mm;
stamens 5–16, scarcely grouped;
styles 0.5 mm;
stigmas broadly capitate.
broadly ovoid to depressed-globose, 4.5–8 × 4–7 mm.
narrowly ovoid to cylindric-ellipsoid, 4–5 × 2–2.5 mm, usually broadest at or near middle.
carinate, 2–2.7 mm;
testa coarsely reticulate.
0.4–0.7 mm;
testa finely linear-scalariform.
= 16 [“18”].
Hypericum sphaerocarpum
Hypericum boreale
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.)
Where Hypericum boreale grows submerged, the plants are almost always sterile with elongated stems and suborbiculate leaves (H. boreale forma callitrichoides Fassett). Such plants intergrade shorewards with typical H. boreale (F. H. Utech and H. H. Iltis 1970). All other chromosome counts for H. mutilum and its near relatives have given n = 8; B. M. Kapoor’s (1972) count of 2n = 18 must be treated with reserve.
Hypericum mutile var. boreale (Britton) E. P. Bicknell is not a validly published name.
The discovery of Hypericum boreale near the mouth of Fraser River at Vancouver in 1989 extends the distribution of this species across Canada almost to the Pacific coast; this occurrence is almost certainly the result of recent introduction.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
KS Wildflowers
MI Flora
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
BC
OR
WA
Flora NW
Go Botany
MD Biodiversity
MN Wildflowers
PNW Herbaria
