Hypericum swinkianum

Hypericum swinkianum
Scientific classification
Kingdom:Plantae
Clade:Angiosperms
Clade:Eudicots
Clade:Rosids
Order:Malpighiales
Family:Hypericaceae
Genus:Hypericum
Section:H. sect. Myriandra
Subsection:H. subsect. Centrosperma
Species: H. swinkianum
Binomial name
Hypericum swinkianum

Hypericum swinkianum, known as Swink's St. John's wort,[2] is a shrub in the St. John's wort family. It was named after Chicago Region botanist Floyd Swink (1921-2000).[2]

Description

Swink's St. John's wort is a many-branched shrub up to 1.8 meters (5.9 ft) high.[1] It has exfoliating bark. The leathery, oblong leaves reach 2 centimeters (3⁄4 in) in width and 5 centimeters (2.0 in) in length, with weakly revolute edges. The flowers are produced in terminal flowerheads known as dichasia. Each dichasium produces 7-31 bright yellow flowers, each with 5 petals and numerous yellow stamens. The capsules are 5-parted. In the Chicago Region, it blooms between July and August.[2]

Hypericum swinkianum differs from the closely related Hypericum kalmianum by its notably larger vegetative features, flowerheads each averaging more than 7 flowers, and an affinity toward acidic rather than calcareous habitats.[1]

Distribution and habitat

Swink's St. Johns wort is known to occur in sand flatwoods and acidic wet to wet-mesic sand prairies in the western Great Lakes region in the United States, including Illinois, Indiana, and Michigan.[2][1] It is a highly conservative species with a coefficient of conservatism of 10 in the Chicago Region[2] and in Michigan.[3]

References

  1. 1 2 3 4 Wilhelm, Gerould; Rericha, Laura (2016). "A new species of Hypericum (Hypericaceae) and some new combinations in the vascular flora of the Chicago Region" (PDF). The Michigan Botanist. 55: 89–96.
  2. 1 2 3 4 5 Wilhelm, Gerould; Rericha, Laura (2017). Flora of the Chicago Region: A Floristic and Ecological Synthesis.
  3. ↑ "Hypericum swinkianum". Michigan Flora. Retrieved 2018-04-10.
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