The New Zealand Plant Conservation Network

Species

Epilobium petraeum

Etymology

Epilobium: From the Greek epi- 'upon' and lobos 'a pod', the flowers appearing to be growing on the seed pod.
petraeum: loves rocks

Common Name(s)

Rock willow herb

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - At Risk - Naturally Uncommon
2004 - Sparse

Qualifiers

2012 - RR, Sp

Authority

Epilobium petraeum Heenan

Family

Onagraceae

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

None

Distribution

Endemic. South Island from the Kaikoura Ranges (Mt Fyffe) south to the Mt Cook Region of Canterbury.

Habitat

A species of exposed, steep, partially stable, sparsely vegetated greywacke rock outcrops, stable to partially stable scree in and near margins of rock outcrops, and occasionally found on partially stable and exposed stream margins.

Features

Compact, densely spreading, glabrous herb producing shrublets up to 400 x 100 mm. Old stems prostrate to spreading; new stems erect, red; not rooting at nodes. Petiole 5-7 mm, slender, channelled, appressed to the stem or slightly spreading. Leaves 15-24 x 4-7 mm, opposite, ovate, elliptic, or broad-elliptic, glossy, erect or spreading, longer than internodes, 3-5 teeth on each margin, upper surfaces dark-green and sometimes flushed red, uppersides red, margin and midrib usually red, base cuneate, apex obtuse to retuse. Inflorescence terminal, conspicuous; flowers perfect, erect; pedicel 2-4 mm long, green; bud pink. Sepals 4, 4-4.5 x 1.2-1.4 mm, oblong, not keeled, red, apex acute. Petals 4, 5-6 x 1.9-2.1 mm, obovate, white, apex notch 0.5-0.8 mm deep. Floral tube 1-1.2 mm deep, c. 2 mm wide. Ovary 12-14 mm, green; style 2.3 mm, white; stigma 1 x 0.4 mm, yellow; filaments white, unequal, longer 2-2.5 mm, shorter 1-1.2 mm. Capsule 35-55 x 1.4-1.8 mm, scarlet-red; pedicel 10-24 mm, scarlet-red. Seeds 1-1.1 x 0.4-0.45 mm, pale brown, papillose but usually flat on one surfave; proximal end constricted with acute apex; chalazal end with a very short, inconspicuous neck; coma 4-5 mm long, white, caducous.

Similar Taxa

Distinguished by the low, spreading, compact habit, all parts glabrous, red stems, opposite, dark-green and glossy leaves with the upper midrib usually red, the leaves not obscuring the internodes, a floral tube 1-1.2. mm deep, and papillose 1-1.1. x 0.4-0.45 mm seeds with a non-persistent coma. It is most similar to E. brevipes Hook.f. which is a glabrescent shrub of similar habitats, with leaves that are initially opposite becoming alternate toward the stem apices. The leaves are narrowly elliptic to elliptic with acute rather than obtuse to retuse apices. A key difference is that the leaf apex in E. breivpes has a distinct apiculus (like a lump of gum) which is absent in E. petraeum. Furthermore the stem leaf junction of E. brevipes has a miniscule tuft of strigulose hairs.

Flowering

December - January

Flower Colours

White

Fruiting

January - March

Propagation Technique

Easily grown in a pot kept in an alpine house or in a rock garden. Prefers a fertile, free draining soil and full sun. Intolerant of warm, humid climates.

Threats

A widespread, naturally uncommon, biological sparse species of high alpine rock habitats. There is no evidence of decline.

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Minute pappate seeds are wind dispersed (Thorsen et al., 2009).

This page last updated on 16 Sep 2014