Friday 16 August 2019

Tiny Plants with a Dark Secret - sundews

Sometimes I just have to stop and take a look around when I am out hiking or walking, there are so many things I know I'd miss seeing otherwise. It makes me wonder whether cyclists and runners know what they are missing out on. It's a fine balance of course, if you're always stopping you never get far, and sometimes far is the place you need to be to see even more amazing sights!

Walking with some botanically minded friends up Clay Ridge in Remutaka Forest Park, meant that there were three of us with sharp eyes. One of us spotted these sundew plants. So we stopped to take a closer look. It helped to have a magnifying glass and lens.
Sundew, photo Ian Goodwin
Sundews are tiny plants with a dark secret. They glisten with a sticky substance and are covered in tiny spikes or tentacles, all the better to catch flies which they trap and then 'eat'.
That's the remains of a dead insect(s) in the centre of this sundew, Photo Ian Goodwin
The sundew can move its tentacles if it feels a fly touch it. The tentacle can move to direct the fly into the sticky centre. There the fly gets stuck and either dies from exhaustion trying to escape or gets smothered. Then the plant uses enzymes to dissolve the insect and absorb the nutrients.   

Of course you don't need to go hiking to find a carnivorous plant, you can buy Venus Fly Trap plants from most garden centres. They are popular presents for children. But I wonder how many children (and adults) know we have these plants in New Zealand too.

It looks like this sundew has trapped a lot of insects, Photo Ian Goodwin
This the sundew looks like without the magnifying lens. 
 Drosera auriculata - tall sundew 
Sundews use insects for food because they usually live in poor soil. The ones we saw on Clay Ridge were growing in clay, which doesn't have much in the way of nutrients.

Some other sundews I've seen were in alpine or sub-alpine zones.
Rosy sundew  - Drosera spatulata - seen on the Heaphy Track, Photo Jon Monk

Drosera stenopetala is a sub-alpine or alpine sundew,
I saw this one in the Tararua Ranges near Jumbo Hut

More information and photos of sundew are here on iNaturalist 

Many thanks to my fellow hikers for their observation skills and great photos.

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