2. Hypericum prolificum Linnaeus, Mant. Pl. 1: 106. 1767.
Shrubby St. John’s wort Shrubby St. John’s wort
Brathys prolifica (Linnaeus) Payer; Hypericum spathulatum (Spach) Steudel; Myriandra ledifolia Spach; M. prolifica (Linnaeus) Spach; M. prolifica var. spathulata (Spach) K. Koch; M. spathulata Spach deciduous, not enclosing capsule, 5, elliptic to obovate or oblanceolate-spatulate, unequal to subequal, 4–8 × 1.5–4 mm; petals 5, golden yellow, obovate to oblanceolate-spatulate, 7–15 mm; stamens deciduous, 150–500; ovary 3(–5)-merous, <placentation incompletely axile>. Capsules usually narrowly ovoid-conic to ovoid, rarely ellipsoid, 7–13 × 4–7 mm. Seeds carinate, 1.5–2 mm; testa linear-reticulate. 2n = 18.
Flowering summer (Jun–Sep). Rocky slopes, embankments, dry stream bottoms, woodland (in north), on limestone or granite; 50–600+ m; Ont.; Ala., Ark., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Ky., La., Md., Mich., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va., Wis.
Hypericum prolificum is variable, the most luxuriant form being found in the southwestern part of its range. Natural hybrids have not been recorded; it hybridizes in gardens with H. densiflorum (H. x\arnoldianum Rehder), H. frondosum, H. kalmianum, and H. lobocarpum (H. x\dawsonianum Rehder).