Ofvers. Forh. Finska Vetensk.-Soc. 48: 73 (1906) APNI
*CVU, *DunT, *EGL, *EGU, *GipP, *Glep, *Gold, *GGr, *HNF, *HSF, *LoM, *MonT, *MuF, *MuM, *NIS, *OtP, *OtR, *SnM, *Strz, *VAlp, *VRiv, *VVP, *WaP, *Wim. A common, declared noxious weed, particularly in dryish areas of the north-east (e.g. Mansfield, Bright, Beechworth, Tallangatta) extending into the alps (e.g. Mt Clear, Mt Skene, Falls Creek areas), but mostly scattered elsewhere.
Herb to c. 80 cm high, usually several erect stems arising from woody, short-rhizomatous root-stock; young stems weakly 2-ridged. Leaves ovate to oblong or linear, 5–25 mm long, 1.5–5 mm wide, margins usually recurved, distantly black-dotted or with black dots confined to apex, lamina with conspicuous translucent glands. Flowers usually numerous in corymbose cymes; sepals linear to lanceolate, 4–7 mm long, acute, connate at base, not black-dotted (rarely with 1 or 2 marginal black glands); petals 2–3 times as long as sepals, pale to deep golden-yellow, black-dotted on the margin; stamens numerous, half to two-thirds as long as petals, shortly fused into 3 bundles; styles 3. Capsule narrowly ovoid, shortly exceeding sepals; seeds short-cylindric, c. 1 mm long, minutely reticulate-pitted.
Robson (2002) recognises 4 subspecies, based largely on distribution. Plants in Australia are included in subsp. veronense. This subspecies has relatively narrow sessile leaves and swollen, diagonal vittae along margins of capsule valves. Most plants reproduce apomictically (i.e. without fertilization) and are, therefore, genetically identical in any area.
In the absence of other feed, stock will graze H. perforatum and commonly suffer photosensitization, affecting lightly-pigmented parts of the body (e.g. inside the mouth), often leading to death by starvation or infection if animals are not removed from infested areas.
|Bioregion||Occurrence status||Establishment means|
|Victorian Volcanic Plain||present||naturalised|
|Central Victorian Uplands||present||naturalised|
|Northern Inland Slopes||present||naturalised|
|East Gippsland Lowlands||present||naturalised|
|East Gippsland Uplands||present||naturalised|
|New South Wales|
|Australian Capital Territory|