It is easily recognized by its dense cespitose habit, the deep blood red juice, the hollow stem, and the crenate or denticulate sterile margin of the cap.
"Studies of American Fungi. Mushrooms, Edible, Poisonous, etc."
George Francis Atkinson
Pelvic plate bearing three anteriorly diverging apophyses, and one denticulate ventromedian process for articulation to opposite plate.
"A New Genus of Pennsylvania Fish (Crossoperygii, Coelacanthiformes) from Kansas"
Joan Echols