11. Hypericum lissophloeus W. P. Adams, Contr. Gray Herb. 189: 21. 1962.
Smooth-barked St. John’s wort Smooth-barked St. John’s wort
Shrubs, erect, sparsely branched, forming dense clumps <sometimes with prop roots>, to 40 dm, <bark smooth and metallic-silvery, without laticifers, exfoliating in thin, curled plates>. Stems: internodes 4-lined at first, soon 4-angled, then terete, <dull silvery, glaucous>. Leaf blades linear-subulate to acicular, (9–)12–17 × 0.5–0.8 mm, <glaucous>, base articulated, parallel or almost so, margins revolute, apex obtuse to rounded, midrib unbranched. Inflorescences <narrowly cylindric>, 1–3-flowered, usually with paired flowers or triads from to 9 proximal nodes. Flowers 20 mm diam.; sepals deciduous, not enclosing capsule, 5, linear-subulate, subequal, 7–8 × 0.5–0.8 mm, <glaucous>; petals 5, bright yellow, obovate-spatulate, 10–12 mm; stamens deciduous, 170–220; ovary 3-merous; <styles 5 mm>. Capsules narrowly ovoid to ellipsoid, 6–7 × 2.5–3.5 mm. Seeds narrowly carinate, 1–1.6 mm; testa coarsely reticulate-sulcate. 2n = 18.
Flowering summer–early fall (Jun–Oct). Pond and lake margins to 1.5 m deep water; of conservation concern; 0–10 m; Fla.
Hypericum lissophloeus is found in Bay and Washington counties. The larger capsules, one- to three-flowered, lateral inflorescence branches, and smooth-polished, metallic bark (that exfoliates like that of Betula species) are among the features that distinguish H. lissophloeus from H. fasciculatum, H. nitidum, and their allies (H. brachyphyllum and H. chapmanii).