Epilobium rotundifolium
Common names
round-leaved willowherb
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Detailed description
Widely creeping, much-branched from base, perennial herb. Stems 100-400 mm tall, initially procumbent soon becoming ascendent and then erect, surfaces strigulose all round but especially so in lines decurrent from the margins of the petioles, often also with a few glandular hairs. Leaves opposite, a few of the uppermost alternate, the lateral veins inconspicuous, 2-5 on each side of the midrib; lamina 3-25 × 3-20 mm, adaxially green to coppery, dull or somewhat glossy, abaxially pinkish or flushed wine-red, broadly to very broadly ovate, acute to rounded at the apex, obtuse to truncate at the base, margins serrate with 5-14 teeth on each side, petiolate, petiole 1-8 mm long. Inflorescence nodding. Flowers erect. Pedicellate, pedicels 2-12 mm long. Ovaries 8-20 mm long, pubescent, investiture comprised of erect glandular hairs. Floral tube 05-1.5 × 0.9-2.0 mm. Sepals 2.0-3.4 × 0.7-1.2 mm, not keeled, subglabrous. Petals 2.5-5.0 × 1.5-3.5 mm, the notch 0.5-0.9 mm deep, white. Stamen filaments white of two types: long (1.2-2.7 mm long) and short (0.7-1.1 mm long), Anthers 0.7-0.8 × 0.6-0.7 mm, yellow. Style 1.4-2.7 mm long, white; stigma 1.0-1.5 x 0.7-0.8 mm, white, clavate surrounded by the anthers at anthesis. Capsule 20-50 mm long, subglabrous to strigulose, on a pedicel 15-42 mm long. Seeds 0.6-0.9 mm long, orange-brown, obovate-elliptic to obovate, finely reticulate-mammillate; coma 4-7 mm long, white to pale brown, caducous.
Similar taxa
Epilobium rotundifolium is easily distinguished from other epilobia by the sprawling growth habit with stems much branched from the base; by the broadly to very broadly ovate serrate often copper-coloured leaves with pinkish to wine-red undersides; nodding inflorescence; evenly pubescent ovaries that are clad in short, erect glandular hairs; sepals which are 2.0-3.4 × 0.7-1.2 mm and not keeled; and by the 0.6-0.9 mm long, orange-brown seeds
Distribution
Endemic. New Zealand: North, South, Stewart and Chatham Islands. Naturalised in Tasmania and the United Kingdom
Habitat
Coastal to subalpine. Frequenting open forest, shrubland and grassland where it usually grows in partial shade on moist stream side banks, rocks within streams and rivers, or on damp banks, amongst boulders and within seepages in forest. Epilobium rotundifolium is also one of several indigenous epilobia that have successfully established within urban environments.
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 - May
Fruiting
October - July
Life cycle and dispersal
Minute pappate seeds are wind dispersed (Thorsen et al., 2009).
Propagation technique
Very easily grown from rooted pieces and fresh seed but inclined to become weedy.
Other information
Where To Buy
Not commercially available.
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
rotundifolium: Round 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.
EPIROT
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.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309
Webb, C.J.; Simpson, M.J.A. 2011: Seeds of New Zealand Gymnosperms and Dicotyledons. Christchurch, Manuka Press.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 30 August 2011. Description adapted from Raven & Raven (1976) and Webb & Simpson (2001).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium rotundifolium Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-rotundifolium/ (Date website was queried)