Hypericum adpressum
Hypericum pseudomaculatum
creeping St. John's-wort
false spotted St. Johnswort
sometimes clustered, internodes not lined, with black glands scattered all over.
usually ascending, sometimes spreading, sessile;
blade usually ovate-lanceolate to triangular-lanceolate or narrowly elliptic, rarely ovate, 18–45 × 6–16(–20) mm, base cordate to rounded, margins plane, apex usually acute, rarely obtuse to rounded, midrib with 3–4 pairs of branches, tertiary veins densely reticulate toward margins, black glands intramarginal (dense) and laminar (scattered).
rounded-corymbiform, 13–60-flowered, narrowly branched, without subsidiary branches.
subcorymbiform to broadly pyramidal, 16–164(–280)-flowered, subsidiary branches ascending to widely spreading.
10–15 mm diam.;
sepals persistent, not enclosing capsule, 5, ovate-lanceolate to lanceolate, subequal, (2–)4–7 × 1–1.5 mm;
petals 5, bright yellow, obovate-oblanceolate, 6–8 mm;
stamens persistent, 60–80;
ovary 3-merous, placentation parietal.
10–20 mm diam.;
sepals not imbricate, erect in fruit, lanceolate to ovate or elliptic-oblong, subequal, (3–)3.7–4.9(–6) mm, apex acute;
petals yellow, usually obovate, rarely elliptic, 6–14 mm;
stamens 38–61;
anther gland amber or pellucid;
styles 5.4–8.5 mm.
ellipsoid to ovoid-ellipsoid, 3.5–6 × 2–4 mm.
broadly ovoid, 3–6 × 2–4 mm, with longitudinal and lateral vittae or vesicles or only ovoid vesicles (all amber).
slightly carinate, 0.6–0.7 mm;
testa scalariform.
not or scarcely carinate, 0.6–0.8 mm;
testa linear-reticulate.
= 18.
= 16.
Hypericum adpressum
Hypericum pseudomaculatum
Hypericum adpressum is more herbaceous and rhizomatous than H. sphaerocarpum and has narrower capsules and smaller seeds.
The plants with aerenchymatous tissue in the rhizome (var. spongiosum) are not taxonomically distinct but merely the result of a habitat-induced modification.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Hypericum pseudomaculatum has been confused with H. punctatum; they are quite distinct and they rarely, if ever, hybridize. The affinities of H. pseudomaculatum are with Mexican H. formosum Kunth.
J. A. Steyermark (1963) recognized two distinct floral forms in Missouri: forma pseudomaculatum with orange-yellow petals and stamen filaments, and forma flavidum in which these parts are pale, creamy yellow. The distribution of these two forms within the whole range of the species is unknown.
Hypericum elatum Aiton (a synonym of H. ×inodorum Miller = H. androsaemum Linnaeus × hircinum Linnaeus) was wrongly cited as from North America by Aiton and was not conclusively recognized as an Old World taxon until J. M. Coulter (1886) published his account of North American Hypericum.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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