Goldfinches beware. Because the teasel - a thistle-like plant with bristly seedheads that are a favourite food of winter bird flocks - has a taste for meat, says Stuart Blackman.
Naturalists have long been intrigued by the teasel’s unusual lower leaves, which wrap around the stem forming steep-sided cups that collect rainwater. Charles Darwin's grandfather Erasmus suggested they function like a castle moat, protecting the upper parts of the plant against attack by herbivorous insects.
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Charles’s son Francis, though, wondered whether the teasels extract nutrients from the decaying bodies of drowned insects in much the same way that pitcher plants do.
Only in 2011 did experiments show that plants supplied with fresh meat produce 30 per cent more seed than those on a flesh-free diet.
There is still debate, though, over whether teasels qualify as full-blown carnivorous plants, because they don’t seem to actively digest their prey. Either way, the teasel does provide clues to how the likes of pitcher plants and Venus flytraps might have started out on the path to carnivory.
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