Kalm's St. John's-wort (Hypericum kalmianum) Linnaeus, 1753 |
Synonyms: Norysca kalmiana |
Hypericum kalmianum is confined to the Lower Great Lakes region in the United States and southern Canada. It grows in sandy or calcareous soils in mesic prairies, fens, dunes, sphagnum-sedge swamps, and rocky shores; 10-400 m. Small shrub, 20-60 cm in height. The leaves are oblong to liner, 3–4.5 cm long. The flowers are 20-35 mm in diameter; 5 golden-yellow petals; in terminal corymbs of 3-7. The fruit is an ovoid capsule. This species flowers from June to August.