Parasites and carnivores

A scary title, but fear not – I’m talking about plants, and the strange ways some of them get their nutrients. I’ve posted about Sundews before, and their habit of eating insects. I recently saw the other species of Sundew found on the Forest (there are three native to the UK, but one doesn’t grow here). Conveniently, the two species are growing side by side, for ease of comparison:

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Round-leaved sundew (Drosera rotundifolia) top right, with Oblong-leaved sundew (Drosera intermedia)

Another unusual way for plants to obtain nutrients is by parasitism. What you can see in the photo below is not those red liquorice bootlaces you used to be able to buy, but a plant that has given up on leaves and photosynthesis altogether. Common dodder sprawls all over other plants, often Gorse, and where it touches its host it essentially taps into its pipework and draws out nutrient-rich sap. It’s a bit like connecting your house’s electrics to next door’s mains. Since the Gorse is doing all the hard work of photosynthesis, the Dodder doesn’t need to, and stopped bothering to produce leaves. It does still flower though – I’ll post a photo if I’m in the right place at the right time.

Common dodder (Cuscuta epithymum)

Common dodder (Cuscuta epithymum)

Interestingly, a plant I have blogged about before – Lousewort – is what is known as a hemi-parasite; it does a similar thing to Dodder, tapping into the roots of other plants, but hasn’t gone so far as to lose its leaves. A ‘belt and braces’ approach, I guess.

Lousewort (Pedicularis sylvatica)

Lousewort (Pedicularis sylvatica)

Steve Alton

Conservation Officer