Chatham Island sow thistle, Embergeria
Embergeria grandifolia (Kirk) Boulos
Vascular – Native
Dicotyledonous Herbs - Composites
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 | At Risk – Recovering | Qualifiers: CD, EF, IE, RR
Previous conservation statuses
2009 | At Risk – Recovering | Qualifiers: CD, EF, IE, RR
2004 | Threatened – Nationally Endangered
Endemic to the Chatham Islands. Found on the main islands and some islets.
Sand dunes (usually the foredunes), also coastal cliff ledges, clay promontories and talus slopes.
Thistle-like herb with stout rhizomes and pale green fleshy leaves up to 1 m long, irregularly divided into toothed lobes. It has a milky sap. Erect flower heads with florets that are light purple to pale yellow. Plant dies down in winter. The plant flowers from December to February and fruits in late summer to autumn.
December - February
Late summer and autumn.
Pappate cypselae are dispersed by wind (Thorsen et al., 2009).
Easy from fresh seed. Does best in a free draining, fertile but damp soil in full sun. Dislikes humidity. Plants are often prone to dying in hot weather.
Domestic stock and other browsing animals (including pigs, possums and rodents) are still a threat on Chatham and Pitt Islands. Competition from invasive exotic plants, coastal development and coastal erosion is also a problem in some areas. However, this species has made a spectacular recovery over large parts of its range, and is actively colonising new areas of beach and coastal cliff. It now occurs in numerous secure sites across the Chatham Island group.
sonchus: Sow thistle
Where To Buy
Occasionally available from specialist native plant nurseries.
Recently Garnock-Jones (2014) advocated that Embergeria should be treated as a synonym of Sonchus. Although this decision differs from the conclusion reached by Heenan et al. (2010) NZPCN has elected to follow this decision.
Fact Sheet prepared for NZPCN by P.J. de Lange 1 August 2003.
References and further reading
Garnock-Jones PJ. 2014: Evidence-based review of the taxonomic status of New Zealand’s endemic seed plant genera, New Zealand Journal of Botany, DOI: 10.1080/0028825X.2014.902854
Heenan, P.B.; Mitchell, A.D.; de Lange, P.J.; Keeling, J.; Paterson, A.M. 2010: Late Cenozoic origin and diversification of Chatham Islands endemic plant species revealed by analyses of DNA sequence data. New Zealand Journal of Botany 48: 83–136.
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
Walls, G.; Baird, A.; de Lange, P.J.; Sawyer, J.W.D. 2002: Threatened plants of the Chatham Islands. Wellington, Department of Conservation.
Please cite as: de Lange, P.J. (Year at time of access): Sonchus grandifolius Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/sonchus-grandifolius/ (Date website was queried)