The Redcap Mycostrums have arisen as a genus common to all the landmasses of Hybarder. Their spores have allowed them to spread across flyways to neighboring continents and islands.They are most successful in wet conditions in tropical and subtropical climates. They are present in temperate regions but live out their lives seasonally as they are unable to survive freezing, and thus not present in polar climates.

Their ancestor was a Ghost Mycostrum from the rainforests of Glicker. It developed two adaptations, poisonous compounds and warning coloration. Evolving in close proximity to the Orpiment Jewel, the Redcaps began stealing their poisons and incorporating them into their own bodies. Over time they were able to acquire the genes to start producing the toxins themselves to deter grazers. Warning coloration quickly followed so as to increase the effectiveness of their deterrence to grazers. The toxins aren't very strong, only causing life threatening conditions in fauna under 20 cm in size and general sickness in any larger fauna, scaling inversely with the organisms body size.

They are otherwise much like their ancestor, living much of their lives as subterranean mycelial networks and reproducing through spores from buds on their fruiting bodies.