Flora of the Southeastern United States

Hypericum radfordiorum Weakley ex J.R. Allison. Common name: Radfords' St. John's-wort, Brushy Mountain St. John’s-wort. Phenology: (May-) Jun-Sep (-Oct). Habitat: Shallow circumneutral soil mats of granitic domes in the Brushy Mountains. Distribution: Endemic to the Brushy Mountains of Alexander and Wilkes counties, NC.

ID notes: The flowers of H. denticulatum, H. erythreae, H. harperi, H. radfordiorum, and H. virgatum are rotate (with petals curved to the right when looking down on the flower from above) and with a somewhat coppery yellow.

Origin/Endemic status: Endemic

Taxonomy Comments: This taxon, included in H. denticulatum var. acutifolium by Webb (1980), differs from typical H. virgatum in being profusely branched from the medial and upper nodes (rather than being little if at all branched, and then only from the uppermost nodes), in having leaves with acuminate (rather than acute to obtuse) apices, and electrophoretically (Webb 1980). Additionally, these plants have numerous bracteal leaves along the inflorescence branches (vs. few or none), the punctate glands of the foliage are large and oval, resembling those of H. denticulatum (vs. small and round), and the punctate glands are distributed on the lower leaf surface and stem (vs. lower leaf surface only). It is notable that these same outcrops are phytogeographically interesting, with other endemics (see Allium keeverae) and disjunct populations. See Allison (2011) for more detailed information.

Synonymy ⓘ: = FNA6, K4, NSProv, POWO, Allison (2011); = n/a — RAB; < Hypericum denticulatum Walter, (included in concept of H. denticulatum (= H. denticulatum var. acutifolium, H. denticulatum ssp. acutifolium) by most earlier authors. Basionym: Hypericum radfordiorum Weakley ex J.R.Allison 2011

Links to other floras: = Hypericum radfordiorum - FNA6

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Heliophily ⓘ: 8