Crimson fungi are a group of fungi characterized by their vibrant red or crimson coloration. They can be found in various habitats, including forests and grasslands, often growing on decaying wood or soil. Their bright color can serve as a warning to potential predators, indicating that they may be toxic or unpalatable. These fungi play an essential role in the ecosystem by breaking down organic matter and recycling nutrients. Some species of crimson fungi are also involved in symbiotic relationships with plants, helping them absorb water and nutrients from the soil. Examples include Mycena haematopus and Cortinarius sanguineus.