Species

Euphorbia glauca

Etymology

Euphorbia: after Euphorbus, a Greek physician who served King Juba of Numidia in 12BC. Juba named a cactus to honour Euphorbus and later Linnaeus named the entire genus after the physician.
glauca: Bloom has thin powder

Common Name(s)

shore spurge, sea spurge, waiu-atua, sand milkweed

Current Conservation Status

2012 - At Risk - Declining

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 - Declining
2004 - Serious Decline

Qualifiers

2012 - CD
2009 - CD

Authority

Euphorbia glauca G.Forst.

Family

Euphorbiaceae

Flora Category

Vascular - Native

NVS Species Code

EUPGLA

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.

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

None

Distribution

Endemic to New Zealand and the Chatham Islands.

Habitat

Coastal cliffs, banks and talus slopes, sand dunes and rocky lake shore scarps.

Features

Perennial herb with multiple erect stems up to 1 m tall and underground rhizomes. Stems reddish; leaves alternate, blue-green. Flowers in terminal bunches, each flower surrounded by a deep red cup-like structure with purple glands. Sap a burning milky juice. Flowers are produced from October to February and fruit occur from December to May.

Similar Taxa

The milky sap distinguishes it from many other coastal herbs. The large cigar-shaped leaves and red cups around the flower-like inflorescences (‘cyanthia’) distinguish this species from other Euphorbia species.

Flowering

September to March (sporadic flowering throughout the year can occur)

Flower Colours

Red / Pink

Fruiting

December to July

Propagation Technique

Easy from fresh seed, cuttings and the division of whole plants.

Threats

Domestic and feral cattle, sheep, pigs and possums are the major threats throughout this species range, mainly through browse and trampling. Competition from taller vegetation is significant at many sites. Coastal development (e.g., road widening) and erosion are further common threats to most populations. Population fragmentation makes the remnants vulnerable to sudden decline. Some populations on the West Coast of the South Island appear to have succumbed to a fungal disease.

Chromosome No.

2n = 20

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Pappate cypselae are dispersed by wind and water (Thorsen et al., 2009).

References and further reading

Benham, S. 2001. Field trip to Hauturu little Barrier island March 2001 and a few observations of Waiuatua shore spurge (Euphorbia glauca). Auckland Botanical Society Journal, 56: 10-43 

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309

This page last updated on 19 Dec 2014