Epilobium nummulariifolium
Common names
creeping willowherb
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
White
Detailed description
Loosely matted, creeping perennial herb forming patches up to 1 m diameter; stems pale purplish, with strigulose hairs running down the lines decurrent from the margins of the petioles. Flowers arising individually from the leaf axils, the stems continuing to grow and root beyond the point where flowers are produced. Leaves opposite, membranous, yellowish-green, usually with red margins and 1-3(-4) inconspicuous lateral veins on either side of the midrib; lamina 3.0-13.0 × 3-11.0 mm, broadly ovate to oblate, obtuse or rounded at apex, rounded to truncate at base, margins remotely and shallowly serrulate with 2-11 teeth on either side; petiole distinct, 1-7 mm long. Flowers nodding, falling before full pedicel elongation is achieved. Ovaries densely grey-strigulose, 6-15-20 mm long, on a strigulose pedicel 7-35 mm long. Floral tube 0.4-1.1 mm deep, 0.6-11 mm diameter, sparsely strigulose without. Sepals not keeled, sparsely strigulose, 1.7-2.1 × 0.4-0.9 mm. Petals white, 1.9-3.4 × 1.7-2.1 mm, notch 0.6-0.8 mm deep. Anthers yellow, 0.5-0.6 × 0.3-0.4 mm, filaments of longer stamens 0.9-1.3 mm long, those of shorter 0.4-1.0 mm, both shedding pollen directly onto stigma at or before anthesis. Style white 1.0-1.5 mm long; stigma white, clavate, 1.0-1.8 × 0.5-0.7 mm, surrounded by anthers at anthesis. Capsule densely grey-strigulose, (10-)15-40 mm long, borne on a strigulose pedicel 23-130 mm long. Seeds brown, 0.7-1.0 × 0.2-0.4 mm, obovoid. minutely papillose; coma 4.0-5.5. mm long, readily detaching or persistent.
Similar taxa
Epilobium nummularifolium could be confused with E. brunnescens. Epilobium nummularifolium is best distinguished from E. brunnescens by the capsules which are copiously invested in grey-strigillose hairs rather than glabrate to sparsely hairy. However, the leaves are also very distinctive; those of E. nummularifolium are yellow-green usually with red-margins, broadly ovate to oblate and distinctly toothed, bearing 2-11 pairs of teeth on the leaf margins. The leaves of Epilobium nummularifolium are membranous, so they wilt readily on picking, whereas those of E. brunnescens are more fleshy so less inclined to wilt quickly. The leaves of Epilobium brunnescens are uniformly dark green, often tinged red or brown, ovate to broadly ovate and usually entire, though sometimes weakly toothed, and then bearing 1-2(-4) pairs of teeth on each margin. In Epilobium brunnescens the pedicel usually completes elongation before the flower drops off, whereas the flowers drop before pedicel elongation has completed in E. nummularifolium.
Distribution
Endemic. New Zealand. North Island (throughout), South Island (mostly in the eastern half), Chatham Islands. Also recorded from Sardinia, Europe
Habitat
Open disturbed ground in forest and grasslands from coastal situations to montane extending occasionally into subalpine habitats. This species is also a common plant of urban areas, wasteland, and plant nurseries where it can be an aggressive weed.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Not Threatened
Detailed taxonomy
Family
Onagraceae
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
September to May
Fruiting
October to June
Propagation technique
Easily grown from seed and rooted pieces. Inclined to become weedy, often an aggressive pest plant in cultivation. A common ‘accidental’ weed transported in the soil beneath nursery raised plants.
Other information
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
nummulariifolium: Coin leaved
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
EPINUM
Chromosome number
2n = 36
Previous conservation statuses
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Raven, P.H.; Raven, T.E. 1976: The genus Epilobium in Australasia. New Zealand DSIR Bulletin 216. Wellington, Government Printer.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange (30 December 2019). Description adapted from Raven & Raven (1976).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium nummulariifolium Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-nummulariifolium/ (Date website was queried)