Classification
 Nomenclature
Scientific Name:
Hypericum perforatum L., Sp. Pl. 785 (1753)
Vernacular Name(s):
goatweed; Klamath weed; Mother Cameron's weed; Saint John's wort
 Description

Herbaceous perennial, woody stock, rhizomatous, up to 1 m high. Stems erect, up to 5.3 mm diam., terete, 2-lined, black glands present on lines, sparse. Leaves 7.0–27.0 mm long, 1.0–9.0 mm wide, elliptic-oblong, lanceolate, linear-lanceolate or oblong-lanceolate, glabrous, reticulate tertiary veins absent; pellucid glands numerous; black glands intramarginal; apex acute, subacute or obtuse; margin entire; base attenuate, cuneate or obtuse; petiole 0.2–0.5 mm long. Inflorescence terminal, panicle of corymbose cymes, flowers 3–16, corolla 8.0–27.0 mm diam. Pedicels 1.2–10.0 mm long. Bracteoles 3.8–5.0 mm long, 0.4–1.0 mm wide, lanceolate or linear-lanceolate, apex acute or acuminate. Sepals 5, 3.0–8.2 mm long, 0.5–1.6 mm wide, more or less equal, not accrescent, narrowly lanceolate; pellucid glands present; black glands sometimes present, scattered; apex acute or acuminate; margin entire. Petals 12.0–14.0 mm long, 5.0–6.5 mm wide, longer than sepals, obovate, golden, black glands scattered on margin and blade, persistent after anthesis. Stamens in 3 bundles, 54–70, 4.0–9.5 mm long, shorter than petals; anthers 0.3–0.6 mm long, anther gland black. Ovary 2.1–4.0 mm long, 1.5–2.8 mm wide, ovoid. Styles 3, 4.6–5.1 mm long, longer than ovary. Fruit capsule, 4.5–8.5 mm long, 2.8–4.0 mm wide, ovoid, brown or light brown, vesicular glands prominent on surface. Seeds 0.8–1.3 mm long, 0.4–0.5 mm wide, oblong, terete, bronze, ribs absent, apices obtuse or rounded.

 Recognition

Distinguished by the stems being terete, 2-lined and the lines with black glands, the leaves with intramarginal black glands, the sepals narrowly lanceolate and usually without black glands, the anthers with a black gland, and the capsule with prominent vesicular glands.

 Distribution

North Island: Northland, Auckland, Taranaki, Volcanic Plateau, Southern North Island.

South Island: Sounds Nelson, Marlborough, Canterbury, Westland, Otago, Southland.

 Habitat

Wasteland, pasture, river beds and banks, roadside, dunes, open scrub, open grassland, gravel pits, railway ballast, glacial moraine and gravels, lake shore, dry sites.

 Biostatus
Exotic
 First Record

Kirk (1869, p. 98). Voucher: WELT SPO87643, 1867.

 Phenology

Flowering: Dec.–May.

 Bibliography
Biosecurity New Zealand 2012: Regional Pest Management Strategies Database. http://www.biosecurityperformance.maf.govt.nz/
Connor, H.E. 1977: The Poisonous Plants in New Zealand. Edition 2. Government Printer, Wellington.
Heenan, P.B. 2014: Hypericaceae. In: Breitwieser, I.; Brownsey, P.J.; Heenan, P.B.; Wilton, A.D. (ed.) Flora of New Zealand — Seed Plants. Fascicle 1. Manaaki Whenua Press, Lincoln.
Howell, C. 2008: Consolidated list of environmental weeds in New Zealand. DOC Research & Development Series 292: 42.
Kirk, T. 1869: On the Botany of the Great Barrier Island. Transactions of the New Zealand Institute 1: 144–157.
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.