Hypericum denticulatum
Perennial herb 0.2-0.7 m tall, erect to ascending, branched mostly from the base, sometimes also from upper part of stem. Stems green, 4-lined, densely gland-dotted, the lowermost portion often becoming brown and spongy-thickened; internodes 8-47 mm long, exceeding leaves. Leaves sessile, spreading from base or usually ascending to appressed, mostly shorter than internodes; lamina 4-20(24) x 3-18 mm, lanceolate or ovate to elliptic or oblong-elliptic or obovate, margin plane but sometimes recurving when dry, concolorous or almost so, not glaucous, subcoriaceous; apex acute to subrounded, base cuneate to rounded-subamplexicaul, sometimes subdecurrent, free; basal veins 1-5, if 1 then with 2-3 pairs of main lateral branches, the midrib otherwise apparently unbran- ched, tertiary reticulation not visible; laminar glands dense on bthsides, not or scarcely prominent until dry. Inflorescence up to c. 25-flowered (terminal), monochasial after c. 4th grade, with up to c. 15-flowered lateral dichasial/monochasial branches from up to 6 nodes below, the whole broadly pyramidal to corymbiform, occasionally with lateral flowering branches below; pedicels 2-4 mm long; bracts 3-6 mm long, lanceolate to subulate. Flowers 5-13 mm in diam., stellate. Sepals 3-8 x 1.5-4 mm, ovate or lanceolate to elliptic or obovate, acute to acuminate; veins 3-5, rarely branched, all prominent; glands linear, distally punctiform. Petals orange-yellow, 5-10 x 4-6 mm, c. 1.6-2 x sepals, obovate; apiculus obtuse; glands linear, interrupted distally. Stamens 50-80, irregularly grouped, longest 3-5 mm long, c. 0.5-0.6 x petals. Ovary 1.5-2 x 1-1.5 mm, ovoid; styles 3, 2-4 mm long, 1.3-2 x ovary, divergent-incurved; stigmas capitate. Capsule 3-5 x 2-3 mm, ovoid to rostrate-subglobose, shorter than to shortly exceeding sepals. Seeds 0.45(0.5-0.65 mm long, testa obscurely linear-reticulate to finely ribbed-scalariform.
2n = 24, 48 (n=12, Webb, 1980; Robson & Adams, 1968). n=24 (Webb, 1980; Rodgers, 1965).
Fields, roadsides, ditches, and open woods on sandy or clay soils (‘sunny places that are poorly drained but seldom subject to prolonged inundation’ – Allison); 0-500 m.
South-eastern U.S.A. (Atlantic and coastal plain from Long Island, New York south to Georgia and northern Florida, west (disjunct) to Tennessee, southern Alabama and Louisiana). Allison’s map (2011) records it from inland N. Carolina.
The disjunct populations of H. denticulatum in the more interior regions (North Carolina, Tennessee) were thought by Webb (1980) to be possibly relicts, whereas he regarded the Alabama population as probably a recent introduction. Allison cited Weakley as suggesting that the Georgia populations should be regarded as adventive.
The Rugel 378 specimen of H. virgatum var. ovalifolium Britton, selected by Rodriguez Jimenez (1973), is not type material. Webb's selection is confirmed here.