Other parasitic plants
Mistletoes aren’t the only parasitic plants – there are lots of others. Many of them are much less obvious than mistletoes and you may walk past some of them every day. That’s because, apart from the mistletoes, most parasitic plants grow on their host’s roots, and above ground many just look like ordinary plants.
Ordinary-looking parasitic plants of Britain and Europe include many hemi-parasitic members of the Scophulariaceae family, and include the familiar Yellow Rattle (Rhinanthus), Red Bartsia (Odontites) and Eyebrights (Euphrasia).
None of these look like parasites – they seem to be innocent-looking wild flowers – but under the ground their roots are busy linking to, and parasitizing, their fellow plants’ root systems.
You can’t easily spot this because they’re hemi-parasitic, and have their own green leaves.
But some of their relatives are holo-parasitic, with no photosynthetic green of their own, and so they are a little more obvious.
Examples of these include the Toothworts (Lathraea), and the Broomrapes (Orobanche).
The Dodders (Cuscuta) are another group of parasites. These are a bit like herbaceous mistletoes, growing up and over their hosts during summer and dying back in winter. Where they touch the host stem they form small haustorial structures, linking into the host plants vascular system. Virtually leafless themselves the Dodders are largely holo-parasitic.
People sometimes get a bit confused by what is or isn’t a parasitic plant. Ivy (Hedera) and Bindweeds (Calystegia and Convolvulus) are often considered parasitic by some gardeners – but they aren’t, they’re just climbers. Other plants (some orchids for example) are saprophytic, living on decaying material from other plants, or have a mutually beneficial mycorrhizal association with soil fungi – but none of those are technically parasitic. And none of these have anything to do with carnivorous plants – those are a different matter altogether.