Even though the deep, dark environments of caves seem like they could never support plant life, certain types of flora thrive in that environment. Caves tend to be damp and have a constant temperature, an ecology that is ideal for plants such as fungi, mosses and algae. Plants can even grow in the electric lights that humans bring along for cave exploration.
Caves are split into three zones: entrance, twilight and dark. The entrance zone still has plenty of light to support many types of plants such as trees and grasses. In the twilight zone, some light is able to penetrate, but it is not enough to support most types of plant life. However, some plants are able to survive in this zone, for example, mosses and ferns. The dark zone has no natural light and can support only the most hardy plants such as fungi and algae.
Plants in the Twilight Zone
As the amount of light decreases, the size and complexity of plant life also decreases. So whereas there may be flowering plants growing in the entrance zone, the twilight zone is typically marked by mosses and ferns. Plants that live in this region of the cave have developed adaptations that allow them to live in such low-light conditions. One such adaptation is that their chloroplasts, the sunlight-capturing molecules in a plant, all gather at the edge of the cell that is closest to the light source.
Plants in the Dark Zone
Even though there is almost no light in the dark zone, plants can still grow. In particular, fungi are adept at living in these dark places. Fungi thrive especially well because caves are full of nutrient-rich bat guano, a perfect soil for mushrooms. Algae can also live in the darkest parts of caves. Instead of using photosynthesis, these algae can use a different metabolic pathway to produce their energy.
Plants can also grow in caves equipped with electric lights. These plants, known as lampenflora, tend to be less vibrant in color and somewhat disfigured. Typically, lampenflora are mosses, ferns and algae. In caves that are lit constantly by lamps, these invasive plants can cause problems to the cave's natural structure or any prehistoric wall art present. Because of their damaging nature, lampenflora are typically controlled through physical, chemical and biological methods.