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Parasitic plants

Mistletoe

The plants take root on branches, from seeds dropped by birds that eat mistletoe berries.

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Dodder

Red flowers are the only part of this leafless parasite that is visible outside the cactus.

Cactus mistletoe

Mushroom-shaped flower stalks emerge from underground stems, which feed on the roots of host plants. Thin stems wrap around a host plant and weaken its immune system.

The pale stems of this plant are parasites of ivy plants.

Thurber’s stemsucker

Helosis

Most plants absorb water and nutrients from the soil to make their own food using energy from sunlight, but others have developed sneakier ways to survive. Parasitic plants pierce the stems or roots of other plants to steal their hard-earned supplies.

Ivy broomrape

Tiny flowers, 2 mm across, bloom along the host stem.

There are two main types of parasitic plants. Hemiparasites (half parasites) can use sunlight to make some of their own food but absorb water, nutrients, and sometimes sugars from the host plants they live on. Some hemiparasites, such as mistletoe and the Australian Christmas tree, will

Eyebright

This tiny wildflower relies on nutrients stolen from the roots of nearby grasses.

The corpse lily has the world’s largest flower, more than 3 1⁄4 ft (1 m) across.

The parasite steals nutrients from the roots of other plants to grow as tall as 14 in (35 cm).

Corpse lily

All parasitic plants have modified roots called haustoria, which enter the roots or stems of host plants to steal food, water, and nutrients.

Parasite

Host plant

The haustoria grow toward the chemical signals given off by the host’s roots. Parasitic plants

Au s t r a l ia n C hr is tm a s tree

The flowers of this plant look and smell like rotting meat.

This tree’s greedy roots can steal nutrients from plants 360 ft (110 m) away.

die if they cannot find a host to steal from. Others, including eyebright and butter and eggs, can survive without a host, although they tend to not grow as well. On the other hand, the second type, holoparasites (whole parasites), cannot make any food of their own and must find a host plant to survive. Some holoparasites, such as dodder, grow above ground. Most, such as the cactus mistletoe, Helosis, Thurber’s stemsucker, and the impressive corpse lily, live within their host plant, emerging only to flower. Parasitic plants do not generally kill their hosts but can weaken them.