Epilobium cinereum
Common name
willowherb
Synonyms
Epilobium billardiereanum subsp. cinereum (A.Rich.) P.H.Raven et Engelhorn
Family
Onagraceae
Flora category
Vascular – Native
Endemic taxon
Yes
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.
EPIBSC
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.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
Brief description
An erect much branched perennial plant, often with an overall reddish look. Leaves fairly small, grey-green to reddish, narrow elliptic, and covered in strigulose hair, with prominent and widely spaced teeth. Flowers very rarely white, often rose tinted, on a strigulose hairy ovary and pedicel.
Distribution
Indigenous. New Zealand: North, South, Stewart and Chatham Islands. Also Australia (Queensland, New South Wales, Victoria, South Australia and Tasmania). Naturalised at least on the Hawaiian Islands if not elsewhere in the Pacific.
Habitat
Coastal to upper montane. In open, often dryer habitats on banks and rock outcrops, as well as around lake, river and ephemeral wetland margins. Often a prominent urban weed, especially in derelict properties, old car yards, and in car parks. In these habitats it often associates with Epilobium ciliatum, E. hirtigerum, E. tetragonum and Lachnagrostis filiformis.
Features
Erect, much branched perennial or annual herb 0.15-0.60 m tall, often reddish-tinged, not obviously stoloniferous; plants strigulose, inflorescence, densely so, hairs comprising an admixture of glandular or non-glandular erect hairs often also present, the stems pubescent all round, conspicuously exfoliating and often somewhat woody near the base. Leaves mostly opposite alternate alternate in the upper half, grey-green, often tinged reddish, densely strigulose, the lateral veins visible to prominent, usually 3-5 on each side of the midrib; lamina 5.0-23.0 × 1.5-7.0 mm, linear to narrowly elliptic, apex subacute to acute or obtuse, base attenuate, margins coarsely serrate, bearing 1-8 teeth on each side, shortly pedunculate or subsessile. Inflorescence erect. Flowers erect. Ovary 10-24 mm long, on a pedicel 0-15 mm long, investiture usually densely though finely strigulose with an admixture of white or greyish-white, glandular or eglandular erect hairs. Floral tube 0.6-1.2 mm deep, 1.2-1.9 mm diameter, usually bearing a conspicuous ring of long hairs within. Sepals 2.5-7.5 × 0.8-1.7 mm, keeled, strigulose, bearing glandular or eglandular hairs also. Petals 3.5-12.0 × 2.0-6.5 mm, the notch 0.8-1.5 mm deep, rose-purple (very rarely white). Stamen filaments white of two types: long 1.5-5.0 mm long and short 1.0-4.5 mm. Anthers cream, 0.5-1.0 × 0.3-0.52 mm. Style 2.5-9.0 mm long, white. Stigma 1.5-4.0 × 0.9-1.5 mm, white, clavate, surrounded by (very rarely held well above) the anthers at anthesis. Capsule 30-68 mm long, densely strigulose, indumentum comprising an admixture of glandular and eglandular erect hairs; pedicel 6-20 mm long. Seeds 0.8-1.0 × 0.3-0.4 mm, brown, reticulate-mammilate to reticulate-papillose, obovoid, chalazal callus absent, apex rounded (not beaked); coma 7.0-10.5 mm long, white, breaking off readily.
Similar taxa
Epilobium cinereum is easily distinguished from all other epilobia except the threatened E. hirtigerum on account of its upright, heavily branched growth habit, finely puberulent, greyish (often red-tinged) stems, foliage, pedicels and capsules, and dark rose-purple flowers which open widely at anthesis. Epilobium hirtigerum is usuall;y easily distinguished from E. cinereum on account of its larger overall size, glabrous stoloniferous winter growth habit, and by the stem hairs which in E. hirtigerum are in mixtures of long, spreading eglandular, shorter glandular and strigulose hairs. In the North Island at least, E. hirtigerum is further distinguished by its smaller, consistently white flowers which scarcely open.
Flowering
September - May
Flower colours
Red/Pink
Fruiting
October - July
Propagation technique
Very weedy and probably best not cultivated as it is inclined to spread rapidly. Epilobium cinereum is a common urban weed in many cities and towns of eastern New Zealand
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
cinereum: Ash-grey
Notes on taxonomy
Raven & Raven (1976) prefer to treat Epilobium cinereum as E. billardierianum subsp. cinereum. However, irrespective of their comments for Australia it is clear that in New Zealand E. cinereum is a widespread, morphologically stable unit that is only occasionally seen sympatric (and even syntopic) with the ecologically and morphologically distinct E. billardierianum. Further hybrids between both subspecies and E. billardierianum are as yet unknown from New Zealand, although Raven & Raven (1976) suggest that they are frequent in Australia. From a New Zealand perspective it is difficult to accept such morphologically distinct species as subspecies because of their reported behavior in Australia. Also, as with any Epilobium, given an opportunity hybridism is likely to happen, even with distinct relatives, as it is the main driver for speciation in the Australasian representatives of the genus. in this regard Raven & Raven (1976) are inconsistent, accepted at species rank other epilobia, which following their treatment of E. billardierianum should also be regarded as subspecies, or even merged.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 22 August 2011. 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. 2001: Seeds of New Zealand Gymnosperms and Dicotyledons. Christchurch, Manuka Press.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium cinereum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-cinereum/ (Date website was queried)