Nature notes
Our carnivorous upland plants
There’s always a moment on a walk when I start to tell the person I’m with about the ‘carnivorous’ plant they’re standing near. The speed with which they move away is worth the slight exaggeration in description, for these plants are more accurately insectivorous, or insect eating. Alarmingly, we have three families of these plants among our uplands: sundews, butterworts and bladderworts.
Carnivory in plants exists to supplement a lack of nitrogenous compounds and salts in the nutrient-deprived soil in which they live. Worldwide there are around 600 known species – most are small and unspectacular. There are five traps that these plants use to ensnare their prey: pitfall, snap, lobster, bladder and fly paper.
British carnivorous plants are all to be found in our peaty, nutrient-poor uplands. Sundews are the largest group in the world – there are 194 known species, of which we have three. Green/red leaves are arranged in a rosette at the base of the plant. These are covered in tendrils and each has a blob of sticky stuff at the tip. The sundew is a fly paper trap species. Any insect stuck to the tendril will eventually be engulfed by the leaf as it curls up around it, then all nutrients will be absorbed by the plant. Summertime means they’ll be showing pinky/white flowers on top of hairless red stems. They favour damp areas, by the side of bogs and streams. Look out for them glistening in the sun. Back in the day, the sticky stuff was collected to use as anti-ageing cream.
The second of our trio is butterwort. Again relying on the fly paper method of catching insects, the pale yellow/green leaves secrete a sticky fluid, trying their best to temptingly attract and rid the hills of the unsuspecting midges that so blight our walks. I’ve often knelt before the star-shaped form of a butterwort plant, gloating over the death of at least three pesky midges. Loving the same kind of habitat as the sundews, look out for a purple flower on a stem raised above the leaves in and around the month of June. The sticky juices secreted from the leaves were often rubbed onto the udders of cows, thought to ward away the Devil and protect the milk within, hence the name butterwort.
Bladderwort. There are meant to be seven species in our portion of the world. The one you’re likely to see is the lesser bladderwort. An aquatic plant, upland acidic pools are the hunting ground of this vicious predator. A delicate yellow flower is held above the water’s surface by a flower stem, but the real action takes place underwater. The plant floats, it has no roots in the soil, and this explains its need to supplement its diet with very small aquatic creatures. It does this via bladders on its underwater stems. These have tiny, sensitive hairs around them that sense movement. When prey is near, a trapdoor springs open (of the bladder trap variety) and the insect gets pulled in with the water around it. The door then shuts and the water is pumped out, leaving the little swimmer entombed. The opening and closing takes place in the blink of an eye. I defy you not to be impressed. The meal is then digested at leisure.
Yes, we’ve all marvelled at the ferocious Venus flytrap before, but to think there’s also drama of a murderous nature going on in those quiet pools up on the moors, places that seem to hold no sense of time or purpose, you can’t help but set out on your next walk with a renewed sense of wonder and awe at the crazy, complex and humbling natural world around us. Who’d have thought plants could be this interesting, and so quietly sinister?
A TRAPDOOR SPRINGS OPEN AND THE INSECT GETS PULLED IN, LEAVING THE LITTLE SWIMMER ENTOMBED