Toxic relationships of the plant world

You haven’t seen a toxic relationship until you’ve seen a parasitic plant sucking the life out of its host. Morbid, I know, especially when Valentine’s Day is coming up! But this is the wonderfully weird and wacky world of plants, and it isn’t all sunshine and roses (literally).

I’m going to talk about some of the most toxic relationships in the plant world, including plants that you might have thought were completely innocent (ahem, mistletoe). But, first of all, let’s take a look at the definition of ‘parasitic plant’…

What is a parasitic plant?

A parasitic plant is one that uses another plant as its life source, drawing all or some of its water and nutrients from its host. Around 1% of flowering plants (over 4,500 species) are parasitic. Believe it or not, all parasitic plants evolved from a non-parasitic species – talk about plants going rogue!

These plants attach themselves to a host plant using modified roots, called ‘haustoria’. This allows them to infiltrate the host plant’s conductive system and extract its nutrients, essentially sucking the life out of its host. This terrifying concept wouldn’t be out of place in a horror film.

Some parasitic plants, however, are actually good for certain ecosystems. For example, certain parasitic plants may be more attracted to an invasive species, saving native species from damage.

Parasitic plant examples

Mistletoe

If you’ve ever kissed under a piece of mistletoe, then you might have kissed under a parasitic plant! Some (not all) mistletoe species are parasitic, and grow on a range of host trees, usually stunting growth and causing the loss of outer branches. In some scenarios, a mistletoe infestation can result in the death of the host tree.

 

Corpse flower (Rafflesia arnoldii)

It produces the world’s largest flower, and is known for smelling like a rotting corpse – but did you know that it’s also a parasite? It grows from the ground, or directly from the stems of its host plant, Tetrastigma, a vine found in subtropical and tropical regions of Asia, Malaysia, and Australia. 

 

Sandalwood trees

Sandalwood is known for being a popular fragrance note featured in many different perfumes, but the tree itself is a parasite that can be found in the same family as mistletoe. Sandalwood is heavily farmed, and once harvested, its host tree is useless. Therefore host trees have to be replanted along with new sandalwood trees when farming.

 

Australian Christmas tree (Nuytsia floribunda)

This eye-catching, bright yellow tree gets its name from the fact that it flowers over Christmastime. It is able to photosynthesise, however, it gets most of its water and other nutrients from surrounding plants – and it doesn’t discriminate! Most other species are susceptible to attack, and its haustoria structure has been known to attach to, and even cut through, underground power cables.

 

Ghost plant (Monotropa uniflora)

Known for its white, ghost-like appearance, this plant does not produce chlorophyll and cannot photosynthesise. Instead, it gets its nutrients from fungi from the Russulaceae family, which in turn get their nutrients from trees. Because it doesn’t need sunlight, it can grow in very dark locations. Super creepy!

Where to find parasitic plants

Parasitic plants can be found all over the world and in all sorts of environments – you can even start the search in your hometown! If you’re in the UK, you’ll find mistletoe in trees across the country. Look a little closer when walking around farmlands to discover dodder (Cuscuta), old gardens to see toothwort (Lathraea) and coastal grasslands to find Knapweed Broomrape (Orobanche eliator).

If you’d like to find out about the ‘healthy’ relationships of the plant world, click here.

Which parasitic plants have you spotted in your local area? Comment below!

 

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