The Ghost Plant
The Ghost plant (also known as Indian Pipe or scientifically as Monotropa uniflora) is a plant that is often thought of as a fungus because it's white and doesn't have any chlorophyll. But it's really a flowering plant in the blueberry family. This plant is one of about 3000 species of non-photosynthetic flowering plants. The Ghost plant can actually grow in dark environments because it is not dependent on light for photosynthesis. You would likely find this plant in dense moist forests with a lot of leaf litter, often in a situation that is too shaded for photosynthesis. Since all of these plants are heterotrophic, they must get their food from an outside source. The Ghost plant gets its food, indirectly, from tree roots. There are some fungi that have a beneficial relationship with tree roots where the tree gives part of its sugars from photosynthesis to the fungi in exchange for nutrients. The ghost plant is a parasite on the fungi, stealing some of these sugars for itself. So the Ghost plant is a plant that is a parasite of a parasite and doesn't need photosynthesis for survival. I think this plant is unique due to the fact that it doesn't use photosynthesis.
As the climate changes and becomes warmer with higher CO2 levels, the effects will be minimal with a possible increase in plant growth. As time goes on the higher CO2 levels will cause the trees to start dying off which will effect the fungi growing on the tree roots. The fungi will then die which will cause the Ghost plant to starve do to no food source. The Higher CO2 levels will cause a chain reaction ending in the extintion of the Ghost plant.