Hypericum mutilum L.
Hypericum mutilum inflorescence with senescent leaves and mature capsules. © Landcare Research 2010.
Hypericum mutilum L., Sp. Pl. 2, 787 (1753)
Herbaceous annual or perennial, not rhizomatous, up to 0.55 m high. Stems erect, usually solitary, decumbent at base, up to 2.2 mm diam., quadrangular, 4-lined, black glands absent. Leaves 7.0–33.0 mm long, 3.0–13.0 mm wide, ovate, oblong, elliptic, ovate-oblong or ovate-elliptic, glabrous, reticulate tertiary veins absent; pellucid glands conspicuous; black glands absent; apex acute, subacute or obtuse; margin entire; base subcordate, truncate or obtuse; sessile. Inflorescence terminal, dichasial cymes, flowers few to many (greater than 50), corolla 3.0–4.0 mm diam. Pedicels 0.2–2.0 mm long. Bracteoles 1.0–2.0 mm long, 0.3–0.4 mm wide, subulate, apex acute. Sepals 5, 1.2–3.5 mm long, 0.3–1.0 mm wide, unequal, accrescent, lanceolate, oblong, elliptic-oblong, linear-lanceolate or linear-elliptic; pellucid glands present; black glands absent; apex acute or subacute; margin entire. Petals 1.8–2.5 mm long, 0.5–1.2 mm wide, longer than sepals, elliptic or elliptic-oblong, pale yellow, black glands absent, persistent after anthesis. Stamens not in bundles 6–16, 1.6–3.0 mm long, shorter than petals; anthers c. 0.2 mm long, anther gland absent. Ovary 1.5–1.8 mm long, 0.5–1.0 mm wide, oblong-ellipsoid. Styles 3, 0.3–0.5 mm long, longer than ovary. Fruit capsule, 3.5–4.7 mm long, 1.6–2.5 mm wide, oblong-ellipsoid, yellow-brown, seed outline protruding through wall. Seeds 0.4–0.6 mm long, c. 0.2 mm wide, oblong, terete, light yellow-brown, ribs absent, apices obtuse or rounded.
Distinguished by its usually solitary, 4-angled stems, the stem base being decumbent and rooting, absence of black glands, the petals being shorter than the sepals, 3 styles, and the mature capsules being thin-walled, oblong-ellipsoid and having the seed outline visible.
Mainly occurs in wet habitats such as roadside ditches, swamps, marshes, and wetlands, where it is often interspersed amongst other vegetation.
Linnaeus, C. 1753: Species Plantarum. Vol. 2. Impensis Laurentii Salvii, Stockholm.
Robson, N.K.B. 1990: Studies in the genus Hypericum L. (Guttiferae) 8. Sections 29. Brathys (part 2) and 30. Trigynobrathys. Bulletin of the British Museum (Natural History). Botany 20: 1-151.