Drosera auriculata (Cormous sundew)
(Unranked): Core eudicots
Species: D. auriculata
Botanical name: Drosera auriculata
Synonyms: Drosera peltata subsp. auriculata
Common name: Tall Sundew, Cormous sundew
Drosera auriculata is one of New Zealand's two species of cormous (producing corms) sundew. It is found throughout the North Island and northern tip of the South Island, below 700m. Also found throughout Southeastern Australia and Tasmania. It is found in peatlands and poor sandy, clay soils and clay banks that are wet in winter but dry out in summer.
It usually begins growth in late autumn to early winter. Initially a rosette is formed about 2-3cm across forming numerous leaves over the course of a month or two. After this a climbing stem emerges from the centre of the rosette and rapidly grows upwards bearing shield-shaped cauline (well-developed stem) leaves every 1-2 cm to a height of about 15-30cm. Plants in shady areas may reach up to 80cm tall! Sometimes a plant may miss the rosette stage altogether and just produce a climbing stem. It develops pink or white delicately scented flowers 10-15mm across in spring to summer. These are terminal on the stem. Within a month or so of flowering the plant withers and turns black. The plant is now resting several centimetres below the surface as a dormant corm. The corm can withstand the dry soil through the summer until autumn rains bring it back to life again.
Drosera species produce a droplet of sticky “dew” at the tip of each hair. Insects are attracted to the fluid, but become stuck. Next, the hairs slowly bend inwards until the whole leaf has folded over the insect. Chemicals released from the hairs digest the insect’s body, and nutrients are taken into the plant.