Do All Plants Use Photosynthesis?

Have you ever wondered do all plants need sunlight in order to survive? Though this may sound like a silly question, it turns out there are quite a few plants that can live with no light at all!

Plant leaves are nature’s solar panels. They excel at converting carbon dioxide, water and light energy into sugar (sugar is energy). A class of chemical compounds called chlorophylls achieves this impressive feat of photosynthesis.

Chlorophylls are the same compounds responsible for the green color of plants. The leaves share this food with the rest of the plant through an intricate network of veins. This sugar, along with nutrients from the soil are the chemical building blocks for plant growth.

Though we generally think of green leaves as a defining feature of plants, this is not always the case. In reality, there are many plants without any chlorophyll. These plants gain their energy by stealing from their neighbors!

The scientific word for a chlorophyll-free-plant is achlorophyllous. Achlorophyllous plants come in a couple different “flavors,” though all are parasitic plants.

 

How do Parasitic Plants Survive Without Photosynthesis?

Some engulf their host plants, sucking their energy like a vampire sucks blood. Others tap into the forest’s underground network of fungi to feed indirectly.

These relationships are called obligate parasitism, meaning finding a host plant is essential for the parasite to live. This contrasts with other plant parasites, such as mistletoe, that can photosynthesize as well as steal nutrients.

What all achlorophyllous plants have in common is their otherworldly appearance – this is a weird bunch. Their bizarre looks have earned them names such as “ghost plant” and “wizard’s net.”

Many grow in ghostly shades of white and orange with microscopic leaves and unusual flowers. If you’re looking for more strange and magical plants check out our guide to real-world magical plants.

Since parasitic flowering plants don’t have any need for sunlight, many only appear above ground as a flower. They often lack the stems, leaves and branches that we would expect from a plant. These parasites look more like alien invaders or strange mushrooms than native plants!

Let’s take a look at a few these peculiar species of parasitic plants.

 

Examples of Parasitic Plants that Don’t Need Photosynthesis

Myco-heterotrophs Survive by Cheating the Fungi of the Forest

The most common variety of parasitic plants are the myco-heterotrophs (which means mushroom-eater in greek). These parasitic plants connect to networks of underground fungi called mycorrhizae to steal the nutrients they need to grow.

Though nearly all plants exchange nutrients through mycorrhizae, the relationship is usually mutual. Most plants receive nutrients and in exchange provide the fungi with sugar.

However, a few groups of plants have stopped returning the favor and started cheating (that’s the technical term). These plants have abandoned photosynthesis in favor of parasitism.

 

ghost pipe fungus

The ghost pipe breaks through the forest floor to reveal its strange, mushroom-like flowers.

  • Ghost Pipe Monotropa uniflora

The unique flowers of Ghost Pipe droop back towards the forest floor. It is easy to imagine a forest spirit using this odd plant to have an afternoon smoke.

 

white plant no photosynthesis

The bloom of a phantom orchid has a ghostly white color.

Photo By: Bill Bouton

  • Phantom Orchid Cephalanthera austinae

This rare and striking orchid is native to the West Coast of the United States and Canada. It grows in dense isolated coniferous forests, and only in soil that contains fungi in the family Thelophoracae.

Housing development and climate change disproportionately affect this delicate plant. Cultivation is difficult due to its unique growing requirements, making extinction a real risk for the phantom orchid.

 

Haustorial Parasites Steal Nutrients from Other Plants

Haustorial (haw-stawr-ee-uh-l, meaning scooping predator in Latin) parasites feed directly on their host plant. They form a sucker called a haustorium (haw-stawr-ee-uhm),  that penetrates the host plants bark. These suckers tap into the host’s vasculature, directly feeding on its nutrients. Some are stem parasites that latch on to the upper reaches of trees. Others are root parasites that grow at the base of a tree and tap into the host’s roots.

 

Root Parasites

 

corpse lily root parasite

The strange looking flower of the corpse lily attracts flies with its putrid odor.

  • Corpse lily– Rafflesia arnoldii

Though many flowers make wonderful perfumes, the flowers of the genus Rafflesia are more likely to repel an admirer, unless that admirer happens to be a fly. The corpse lily has a pungent odor of rotting flesh, used to attract the flies that pollinate this stinky flower.

The corpse lily can grow up to 17 inches in diameter, making it the largest flower in the world. The corpse lily’s intense aroma, combined with its massive size make it quite unique, even for a parasitic plant.

 

broomrape plants no photosynthesis

The dense bloom of a broomrape looks like a flowering pinecone.

Photo By: Scott Darbey

  • Broomrape Orobanche

Broomrape is a parasitic plant that is closely related to many common wildflowers, including snapdragons, Indian warrior and Indian paintbrush. The flowering stalk of this parasite mimics a pinecone poking up through the forest floor. They could easily be mistaken for a pinecone if it weren’t for the flowers growing between the scales.

Stem Parasites

 

dodder

A dodder vine consumes a sage bush.

Photo By: Stan Shebs

  • Dodder Cuscuta

This vining parasite looks like a mess of silly string sprayed over its victim. It grows quickly and needs no roots. Instead, it relies exclusively on the suckers it sinks into any plant unfortunate enough to lie in the dodder’s path. Dodder also is able to hack into the genes of its host for the purposes of making the plant more vulnerable later on.

This aggressive weed quickly starves bushes and trees, choking out their sunlight before moving on to the next host.

The thick matt of orange strands looks less like a plant than a fishing net. Dodder’s odd appearance has inspired common names such as wizard’s net, devil’s hair and goldthread.

 

Pilostyles hamiltonii

The tiny blooms of pilostyles make up for their size with their dense clusters of flowers.

Photo By: Kevin Thiele

  • Thurber’s stemsuckerPilostyles thurberi

This sneaky parasite lives entirely within the stems of legumes (plants in the pea family). Keep your eyes peeled for this rare plant if you are wandering in the American Southwest.

It is rarely noticed since it only becomes visible in January when its tiny blooms open up off the stem of the host plant. Even when the flowers do arrive you will be lucky to spot them. The blooms are a mere 3 millimeters across, about the width of a pencil’s lead.

Though other members of the genus Pilostyles can infect various legumes, the American variety primarily attacks a small desert plant called dyeweed (Psorothamnus emoryi).

We hope you have enjoyed learning about this small selection of the numerous species of parasitic plants. Download the PlantSnap app to identify parasitic plants in the wild!

 

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