Lysimachia vulgaris
Common name
Yellow loosestrife
Family
Primulaceae
Flora category
Vascular – Exotic
Structural class
Herbs - Dicotyledons other than Composites
Conservation status
Not applicable
Brief description
Tall (up to 1 m) plant with paired (or 3 or 4’s) willow-like leaves up the more-or-less upright stems, groups of 10 or more yellow flowers, 1.5 cm across.
Distribution
Scattered distribution, two sites in the Waikato and scattered sites in southern Westland.
Habitat
Wet grassland and the margins of water bodies.
Detailed description
Summergreen herb; stems erect, ± minutely glandular-hairy, to c. 1 m tall, arising from underground rhizomes. Lvs opposite, shortly petiolate to subsessile. Lamina 4-11 × 1.5-4 cm, lanceolate to ovate or elliptic, glabrous above, minutely glandular-hairy beneath and dotted with black glands, entire; base cuneate to rounded; apex acute. Panicle terminal, many-flowered, glandular-puberulent, with leaflike bracts subtending lower branches; upper bracts subulate to lanceolate. Pedicels often > fls. Calyx 4-5 mm long; lobes lanceolate, acuminate, rounded at base, glandular-ciliate and dark-margined. Corolla limb c. 2 cm diam., yellow, often with pinkish flush towards base, dotted with minute glands; lobes 7-10 mm long, ± elliptic-oblong. Stamens 3-5 mm long; filaments united to c. ⅓ length, densely glandular-scaly. Style > stamens, glabrous. Capsule 3-4.5 mm diam., ± globose. Seed broad-ellipsoid, flattened with thick rounded margin.
Similar taxa
Non-flowering plants are similar to purple loosestrife (Lythrum salicaria) but in yellow loosestrife the upper surface and edges of the leaves are dotted with black or orange glands.
Flowering
December to April
Flower colours
Yellow
Fruiting
Autumn
Life cycle
Seed spread by water movement, deliberate planting or garden discards
Year naturalised
1940
Origin
Europe, temperate Asia
Reason for introduction
Ornamental plant
Control techniques
Not controlled in New Zealand.
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Webb et al. (1988).
References and further reading
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand Volume 4: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch.
Clapham, A.R.; Tutin, T.G.; Warburg, E.F. (1962). Flora of the British Isles. Cambridge University Press, Second Edition. 1269pp.