The New Zealand Plant Conservation Network

Species

Epilobium billardiereanum

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

Common Name(s)

willowherb

Current Conservation Status

2012 - Not Threatened

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Epilobium billardiereanum (Ser.) DC.

Family

Onagraceae

Flora Category

Vascular - Native

NVS Species Code

EPIBIL

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

Epilobium billardiereanum (Ser.) DC. subsp. billardiereanum

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). 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.

Threats

Not Threatened

Chromosome No.

2n = 36

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

This page last updated on 3 Jan 2020