Parasitic organisms are usually fascinating things with complex life cycles and incredible trickery to deceive their hosts. The Cuckoo and ticks spring to mind as obvious animal parasites but there are also parasitic plants, including some great examples in tropical forests – but we have our own here in Britain; a vampire vine with red stems. This parasite is called Dodder and while on a walk in Devon last week I came across a large patch of it smothering a Gorse bush, one of its favourite hosts, this sighting galvanised me into doing some research and today I bring you these intriguing facts.
- Cuscuta europaea is the red-stemmed species of Dodder found across Britain, there are 170 species in the genus Cuscuta, found from temperate to tropical habitats, formerly in their own family Cuscutaceae, Dodders are now part of the Convolvulaceae (Bindweed) family.
- Dodder has no functioning leaves, no chlorophyll (the crucial element in photosynthesis) and no roots, it is literally just a stem that relies entirely upon its host plant for all of its nutrition and water.
- Dodder uses specialised growths called Haustoria to pierce the hosts stems, inserting itself into the vascular system so that it can then absorb sugars and fluids.
- Dodder does produce flowers in the summer held on globular inflorescences much the same colour as the stem, once pollinated the seeds are released onto the soil below where they can remain viable for up to 10 years.
- When the Dodder seed germinates it uses energy stored in the seed to grow in search of a host plant, it senses the direction of a host using airborne volatile organic compounds emitted by plants – essentially it sniffs them out. But it has to find a host within 10 days or it dies.
- Dodder have varying host species depending on the species and habitat but in Britain it is largely found on Heather and Gorse but can use Lucerne, clovers & ivy.
- Being such a distinctive plant it has many varied folk names, some of the best include; ‘wizard’s net’, ‘devil’s guts’, ‘hellbine’, ‘strangleweed’, ‘witches hair’ and ‘goldthread’.
- In some countries Dodder can be a major agricultural pest where it parasitises food crops such as Alfalfa, potatoes and flax and can be difficult to remove.
- Dodder weakens its host which makes the plant more vulnerable to diseases and viruses – Dodder can also aid transmission and spread of plant disease if it is connected to multiple hosts.