Disguised in the bush – a plant mimic

Last weekend, when I should have been writing grant applications, I was dragged out for a bush-walk. However, my arm didn’t have to be twisted too hard, since it was a fine day and the track between Kiriwhakapapa and Blue Range is lovely (although steep).

Alseuosmia pusilla

Alseuosmia pusilla

Alseuosmia pusilla was abundant along the track. This is a very interesting little shrub. It looks a LOT like a juvenile of the completely unrelated horopito (Pseudowintera colorata) tree, which is also known as pepper tree because its leaves have a peppery taste.  (Horopito is sometimes also called “ice cream plant” to the uninitiated…)

horopito, pepper tree, Pseudowintera colorata

Horopito, pepper tree, Pseudowintera colorata

It’s been suggested that this is a case of mimicry, the palatable Alseuosmia pusilla mimicking the unpalatable horopito, although this is controversial.

The similarity is certainly sufficient to often fool me, until I take a good look (the Alseuosmia flowers and fruit are very different to horopito) or have a little taste of the leaves.

Fruit of Alseuosmia pusilla

Fruit of Alseuosmia pusilla

There are only a few species of Alseuosmia, and they are all only found in New Zealand. They are fantastically morphologically-variable, and it can be difficult to work out which species is which. The tallest species, A. macrophylla (toropapa or karapapa) has big flowers that are often very colourful. They are also heavily scented, such that the plants are often smelt before they’re seen!

Alseuosmia macrophylla, from near Auckland

Alseuosmia macrophylla, from near Auckland

Te Papa’s collection includes a specimen of Alseuosmia macrophylla collected in 1769 during Captain Cook’s first expedition to New Zealand.  You can view it here.

4 Responses

  1. Leon

    Hi Leonie,
    Sorry for my slow reply, but I’ve been away on field-work. You can email your photo to leonp@tepapa.govt.nz, and I will have a go at identifying it.
    Leon

    Reply
  2. Leonie

    Hi,
    This has nothing to do with this plant, but I was wondering if you could help me identify a tiny plant I photographed in the bush with little red berries on it. If you can give me an email address I will send the pic through. Google has failed me this time!
    Thanks :)

    Reply
  3. Leon Perrie

    It’s a trick. People who doesn’t know the plant are often told that it tastes like ice-cream. They have a nibble, and the taste is hot and peppery. It may be not very nice, but they’ll remember the plant (is trickery a valid learning device? Of course, not something I condone…). NB. horopito is increasingly being used to flavour sauces etc.

    Reply
  4. jane

    Why is horopito called an ice cream plant?

    Reply

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