Hypericum adpressum

W. P. C. Barton
Comp. Fl. Philadelph. 2: 15. 1818.
Common names: Creeping St. John’s wort
Endemic
Synonyms: Brathydium fastigiatum (Elliott) K. Koch Hypericum adpressum var. fastigiatum (Elliott) Torrey & A. Gray H. adpressum var. spongiosum B. L. Robinson H. bonaparteae (W. P. C. Barton) K. Koch H. fastigiatum Myriandra adpressa
Treatment appears in FNA Volume 6. Treatment on page 83. Mentioned on page 75, 84.

Inflorescences rounded-corymbiform, 13–60-flowered, narrowly branched, without subsidiary branches. Flowers 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. Capsules ellipsoid to ovoid-ellipsoid, 3.5–6 × 2–4 mm. Seeds slightly carinate, 0.6–0.7 mm; testa scalariform. 2n = 18.


Phenology: Flowering late summer (Jul–Sep).
Habitat: Marshes, pond margins, wet ditches, bogs, coastal plain
Elevation: 0–1000 m

Distribution

V6 136-distribution-map.jpg

Conn., Del., Ga., Ill., Ind., Md., Mass., Mo., N.J., N.Y., N.C., Pa., R.I., S.C., Tenn., Va., W.Va.

Discussion

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.

Selected References

None.

Lower Taxa

None.

... more about "Hypericum adpressum"
Norman K. B. Robson +
W. P. C. Barton +
Undefined sect. Myriandra +
Creeping St. John’s wort +
Conn. +, Del. +, Ga. +, Ill. +, Ind. +, Md. +, Mass. +, Mo. +, N.J. +, N.Y. +, N.C. +, Pa. +, R.I. +, S.C. +, Tenn. +, Va. +  and W.Va. +
0–1000 m +
Marshes, pond margins, wet ditches, bogs, coastal plain +
Flowering late summer (Jul–Sep). +
Comp. Fl. Philadelph. +
Brathydium fastigiatum +, Hypericum adpressum var. fastigiatum +, H. adpressum var. spongiosum +, H. bonaparteae +, H. fastigiatum +  and Myriandra adpressa +
Hypericum adpressum +
Hypericum sect. Myriandra +
species +