Epilobium billardiereanum
Common name
willowherb
Synonyms
Epilobium billardiereanum (Ser.) DC. subsp. billardiereanum
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.
EPIBIL
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 | Not Threatened
Previous conservation statuses
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Brief description
A distinctly coastal species, generally found in sandy ground, with a decumbent habit, narrow ovate to ovate leaves with fine teeth, and flowering stems erect with a dense covering of white grey striglose hairs on the upper stems, pedicels, capsule ansd sepals.
Distribution
Indigenous. New Zealand: North, South, Stewart and Chatham Islands. Also Australia (New South Wales, Victoria, South Australia and Tasmania).
Habitat
Coastal. Usually on sparsely vegetated damp sand flats, or sandy ground bordering slow flowing streams, lagoons, ponds and lake margins. Often found in association with oioi (Apodasmia similis), wiwi (Ficinia nodosa) and Juncus spp. On the Chatham Islands, E. billardierianum is occasionally found inland growing on sandy ground in seasonally damp ground or around permnanent water bodies.
Features
Decumbent, prostrate, widely spreading, sparingly to well-branched perennial herb forming rather open, ± circular patches up to 1 m diameter, and up to 0.95 m tall (where plants have pushed up through surrounding vegetation), with flowering branches ± weakly ascendent. Branch stems ± glabrescent to weakly strigulose; inflorescences densely grey-strigulose with glandular and eglandular hairs absent, branch bases ± woody, and often conspicuously exfoliating in well established specimens. Leaves mostly opposite alternate in and near the inflorescence, or alternate in the upper half, subsessile, yellow-green, green, often red-tinged, glabrous and shining the lateral veins visible to prominent, usually 3-5 on each side of the midrib; lamina 5.0-40.0 × 6.0-20.0 mm, narrowly ovate to ovate, base rounded to truncate, apex obtuse, margins densely and evenly serrulate, bearing 16-40 teeth on each side. Inflorescence on ascending branches, ± erect. Flowers erect. Ovaries densely grey-strigulose erect hairs, 10-30 mm long, on a pedicel 2-16 mm long. Floral tube 0.6-2.1 mm deep, 1.4-2.8 mm diameter, often bearing a conspicuous ring of long hairs within. Sepals 2.5-7.8 × 0.9-2.1 mm, keeled, strigulose.Petals 3.7-7.0 × 3.0-5.0 mm, the notch 1.0-1.8 mm deep, white flushing rose-purple after fertilisation. Stamen filaments white of two types, long 1.5-2.4 mm long and short 0.8-1.4 mm. Anthers cream, 0.5-1.0 × 0.3-0.65 mm. Style 1.1-2.0 mm long, white. Stigma 1.5-4.0 × 0.9-1.5 mm, white, clavate, surrounded by anthers at anthesis. Capsule 30-75 mm long, densely strigulose; pedicel 6-12 mm long. Seeds 0.9-1.1 × 0.3-0.4 mm, brown, reticulate-mammilate to reticulate-papillose, obovoid, without a chalazal callus, apex shortly beaked; coma 7.0-10.5 mm long, white, breaking off readily.
Similar taxa
Easily distinguished from other New Zealand epilobia by its ecological preference for damp sandy ground in coastal habitats, large size, stoloniferous, decumbent growth habit with only weakly ascendent, branch tips, erect inflorescences, glabrescent stems, yellow-green, green to red-tinged, glabrous, narrowly ovate to ovate leaves with rounded to truncate bases and obtuse apcies and whose leaf margins are densely and evenly serrulate, bearing 16-40 teeth either side, and by the densely grey-strigulose (glandular and glandular hairs absent) inflorescences and capsules, and white flowers (which are only faintly rose-tinged after fertilisation). The species is superficially similar to E. rotundifolium as both have similar leaf shape and growth habit, but the teeth on the leaves of E. billardierianum ar much finer than those of E. rotundifolium, the flowers on E. billardierianum are significantly larger, and the dense covering of hair on E. billardierianum is more obviously white gray in colour. In New Zealand at least Epilobium billardierianum has no similarity whatsoever to the strictly erect, much-branched, grey-coloured, E. cinereum (see Taxonomic Notes under E. cinereum) with which it sometimes grows. Both species are amply distinct from each other, and as far as is known do not hybridise with each other in the wild.
Flowering
October - March
Flower colours
White
Fruiting
December - July
Propagation technique
Easily grown from rooted pieces and fresh seed. Does best planted in full sun in a damp sandy soil. Inclined to be weedy and probably best left for restoration plantings into dune field rather than general cultivation.
Substrate
Sand
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
billardiereanum: Named after Jacques Houttou de Labillardiere (1755-1834), 19th century French botanist who described several New Zealand plants
Notes on taxonomy
Raven & Raven (1976) prefer to treat Epilobium billardierianum as E. billardierianum subsp. billiardierianum, and E cinerium as E. billardierianum subsp. cinerium. 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 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 28 August 2011. Description prepared by P.J. de Lange (28 August 2011) 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.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium billardiereanum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-billardiereanum/ (Date website was queried)