Aciphylla dieffenbachii, also called soft speargrass or Dieffenbach's speargrass, is a species of soft speargrass endemic to the Chatham Islands.
It is a small perennial with clusters of soft and drooping leaves that divide into blue-green leaflets up to long.[1] [2] It produces a striking upright flowering stem up to tall.[3] From November to February it produces yellow flowers, and from January to June it produces a golden-yellow fruit that turns a light brown-grey when mature. It has a robust and deep taproot. If damaged, it will bleed a sticky white latex fluid.
It is endemic to the Chatham Islands. Within the Chathams, it has been found on the Chatham, Pitt, Mangere, Little Mangere, and South East (Rangatira) islands, along with some of the Murumuru stacks and islets. It is found solely in coastal areas.
It has also been cultivated, and can be found in gardens on mainland New Zealand.[4]
Aciphylla dieffenbachii is named after Johann Karl Ernest Dieffenbach, a German physician, geologist and naturalist. Dieffenbach worked for the New Zealand Company and travelled widely across the country.
As of 2023, it was classified as At Risk – Declining.