sonchus

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Sonchus grandifolius just starting to flower Te Henga. Image: Peter J. de Lange

Sow thistle gets a name revival and a little rusty

Last year the Chatham Islands lost one of its unique genera. The endemic Chatham Islands sow thistle was originally described by New Zealand botanist Thomas Kirk (1828–1898) as a new species of Sonchus, S. grandifolius (Kirk 1894). Then in 1965 botanist Loufty Boulos transferred S. grandifolius and the Australian endemic S. megalocarpus to a new genus Embergeria (Eichler 1965). Later Nicholas Lander (Lander 1976) transferred the Australian Embergeria megalocarpus to another new endemic Australian genus Actites leaving the Chatham Islands E. grandifolius the sole representative of the genus Embergeria, which by default was now a Chatham Islands endemic.

Chatham Island sow thistle in flower. Image: Peter de Lange

Spectacular comeback for Chatham Island Sow-thistle

The Chatham Islands Sow-thistle or Embergeria grandifoliais one of two endemic plant genera known only from the Chatham Islands. For most of the last fifty years the sow-thistle has been in decline throughout the Chatham Islands such that at one time it was ranked by the International Union for the Conservation of Nature (IUCN) as “Endangered” meaning that if the decline wasn’t halted it would soon go extinct.

Since the late 1990s the Department of Conservation in cooperation with Chatham Islanders has been working to save this peculiar plant from extinction. While Chatham Island sow-thistle is probably not the most attractive looking of plants it is undoubtedly of world wide interest. Superficially resembling the introduced puwha/sow-thistles (Sonchus spp.), the Chatham Islands Sow-thistle is a much larger plant with flowering specimens sometimes reaching up to 1.8 m in height. The yellow-green leaves are very leathery and can be up to 1 m long, while the dense clusters of daisy-like flowers are produced in profusion and multi-coloured in shades of yellow, apricot and purple.