Collariella bostrychodes is a fungal decomposer of lignin and carbohydrate in the family Chaetomiaceae commonly found in soil and dung. The fungus is distinguished by a darkened collar-like ostiole around the ostiolar pore, giving the fungus its name. The fungus is highly variable in shape and form, giving raise to the belief that there are two subclades in the species. The ascospores range from lemon-shaped to nearly spherical with slightly pointed ends. It can grow to be pale green and later turn pale bluish grey or olivaceous with age. The fungus produces the toxic secondary metabolite, chaetochromin.