Epilobium hirtigerum
Common name
hairy willowherb
Synonyms
Epilobium junceum G.Forst. var. hirtigerum (A.Cunn.)Curtis, E. junceum sensu Hook.f. pro parte, E. tetragonum L. E. brasiliense Hausskn., E. sarmentaceum sensu Back. et Bakh., E. cinereum sensu Raven prop parte.
Family
Onagraceae
Flora category
Vascular – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Herbs - Dicotyledons other than Composites
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.
EPIHIR
Chromosome number
2n = 36
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2018 | At Risk – Recovering
Previous conservation statuses
2012 | Threatened – Nationally Critical | Qualifiers: DP, EF, SO
2009 | Threatened – Nationally Critical | Qualifiers: DP, EF, SO
2004 | Data Deficient
Distribution
Indigenous. New Zealand, North, South and Chatham Islands. Also known from Australia, Indonesia and South America.
Habitat
Coastal, lowland to montane. A short-lived species of open ground, seepages on cliff faces, sparsely-vegetated wetland margins, braided riverbeds, lake edges, and swamps. Now most common in urban areas and associated wasteland.
Features
Robust perennial, stoloniferous, dull grey to grey-green, reddish tinged herb, 0.2-1.8 m tall. Plants distinctly hairy, all parts except petals densely covered in long spreading, and short erect, eglandular, greyish hairs; hairs of inflorescence glandular. Stems usually unbranched; woody near base. Stolons numerous (especially in winter), arising from base of stems, and sometimes from rootstock, dark red, glabrescent. Stolon leaves bright green, streaked, tinged or blotched dark red, glabrous, 50-80 × 10-40 mm, broadly ovate,to elliptic, base oblique to broadly cuneate, sometimes attenuate, apex acute to obtuse, sometimes rounded, margins coarsely and ± evenly serrated, teeth up to 18 on each side; lateral veins 2-4 each side of midrib, conspicuous. Leaves of stems and inflorescences alternate except near base where opposite, glaucous, hairy; 15-60 × 2-8 mm, linear to narrowly lanceolate, base acute or acuminate, apex acuminate, margins coarsely serrate, sometimes undulate, teeth 0-12 on each side, evenly distributed or concentrated toward leaf apex; lateral veins 2-4 each side of midrib, usually inconspicuous. Inflorescence erect. Flowers erect, up 16 mm diameter. Pedicel 0-70 mm long. Ovaries 14-30 mm long, invested with spreading, appressed, glandular hairs. Sepals keeled, 2.5-5.3 × 0.8-1.0 mm, invested with spreading, appressed, glandular hairs. Floral tube 0.5-0.9 mm deep. 1.0-1.5 mm diameter at apex, internally bearing a conspicuous ring of long white hairs. Petals white (North and South Island) or rose-pink (South Island), 2.8-8.0 × 1.8-5.2 mm wide, notched, notch 0.6-1.8 mm deep, petals of white-flowered plants often shorter than sepals, scarcely spreading apart at anthesis, petals of rose-pink –flowered plants longer than sepals, spreading widely at anthesis. Stamens 8, of two lengths, 4 longer (0.8-4.0 mm) and 4 shorter (0.3-0.5 mm); anthers 0.5-1.2 × 0.3-0.5 mm, cream. Stigma rarely positioned above lower set of stamens; style 1.2-4.2 mm long, white, basally invested in long hairs; stigma clavate, 0.6-2.4 × 0.6-0.9 mm. Capsules on pedicels 6-15 mm long; narrowly cylindric, 35-60 mm long, densely pubescent with both long, spreading, appressed, eglandular, and shorter, erect, glandular hairs. Seeds 0.9-1.1 × 0.5 mm, orange-brown, obovoid, papillose; coma easily detached, 5-8 mm long, white.
Similar taxa
Hairy willow herb is most often confused with Epilobium cinereum which is commonly found growing in the same habitats. Epilobium cinereum differs from hairy willow herb by its smaller, spreading rather than erect growth habit, non-dimorphic, smaller (up to 40 × 7 mm), coarsely toothed leaves, larger (up to 20 mm wide), consistently dark rose-purple flowers than open widely, and slightly smaller (0.8-1 mm) seeds.
Flowering
September to May
Flower colours
Red/Pink, White
Fruiting
November to June
Propagation technique
Easily grown from seed and rooted pieces of stem. Prefers full sun and does best in damp ground. Despite its scarcity in the wild in cultivation this species can quickly become invasive.
Threats
Most recent (i.e. last 15 years) records are from urban situations, country roadsides, within coastal areas or under willow (Salix spp.) along river banks. Plants are usually in wasteland, often within new housing developments, bordering drains, within old quarry pits or growing in cliff seepages. A common habitat is car parks, traffic islands and roadside gutters. In these sites some quite large populations have been destroyed by housing, road works and through competition from large, faster growing weeds. However, overall it now seems clear that this species is increasing its range rather than in decline.
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
Notes
Most New Zealand plants have white flowers, with only a few instances of rose-purple coloured flowers (the more usual colour form in Australia) are known.
Attribution
Fact sheet first prepared for NZPCN by P.J. de Lange 6 January 2008. Description adapted from Raven & Raven (1976) and Webb & Simpson (2001).
References and further reading
Raven, P.H.; Raven, T.E. 1976: The genus Epilobium in Australasia. New Zealand DSIR Bulletin 216. Wellington, Government Printer.
Webb, C.J.; Simpson, M.J.A. 2011: Seeds of New Zealand Gymnosperms and Dicotyledons. Christchurch, Manuka Press.
Citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium hirtigerum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-hirtigerum/ (Date website was queried)