Nick Baker’s hidden Britain
The creeping common dodder
Folk call it many names: devil’s hair, love vine, devil’s ringlets, angel hair, wizard’s net, strangleweed, witch’s hair and devil’s guts, to name a few. Scientists call it Cuscuta epithymum, but you may know it as common dodder – and it’s as good or as bad as all these names might suggest.
Over the summer, this strange plant can be found draping itself over clumps of vegetation in many of the UK’s heath habitats. A weird capillaceous mass, it looks and behaves in a very un-plant-like manner; especially since it is lacking a major defining characteristic of most plants, and that is verdure or, for that matter, anything that even resembles a leaf (these are present but only as vestigial scales on the stem).
If you were to look inside its cells, you wouldn’t find a speck of chlorophyll – that almost magical pigment that harvests the light of the sun and turns it, with the help of water and carbon dioxide, into the very stuff of life. So, instead of a hue of green, dodder has an almost fleshy pink pigment. With no
photosynthesis going on, this plant has to get all it needs from somewhere else. It is a rare example of what is known as a holoparasite: a botanical vampire that steals all that it needs from others.
Normally, dodder is quite subtle, and its strange limbs get lost amongst the vegetation through which it creeps. But in some places, it is so successful that it almost smothers its host plant under a pink blanket, looking like a Silly String fight in a fairy princess’ parlour. When it blooms, it further enhances its almost benign appearance, turning itself into floral bunting as small clusters of dark-pink-centered pompom flowers erupt periodically along its tendrils.
Dodder starts like most other annual plants. Tiny seeds that have lain dormant in the soil start to germinate in the spring. Simple roots grow down to anchor the seedling, while the pale tendrils stretch upwards – so far quite normal. However, while most other seedlings will eventually terminate in some leaf-like structures, our dodder doesn’t. Instead, as it snakes its way upwards, it is relying on the rapidly dwindling resources contained within the seed. It is so dependent on finding a host of the right sort, that if it doesn’t find a gorse, thyme or heather plant within less than five days, it will wither and die.
Getting a grip
Once it makes physical contact, the dodder winds itself around the stems. Little swellings called haustoria appear, and from their underside tubes grow out into the tissues of the plant. These inject ‘microRNA’ molecules that jam the host plant’s immune system and stop it from sending clotting proteins to the sites of invasion. So the parasite can now send its plumbing deep into the host’s water and food circulation system, effectively diverting the sap for its own needs.
It’s at this stage that the dodder severs its contact with the earth and become the most ‘unplantly’ plant; its roots wither along with the lower portions of its stem. Free from its earthly tethers, it clambers up with sinister enthusiasm, tapping into the host as it goes, and climbing from plant to plant – linking them together with an alien pipeline.