 The specific epithet indigo is derived from the Latin word meaning " indigo blue " . Its names in the English vernacular include the " indigo milk cap " , the " indigo Lactarius " , the " blue milk mushroom " , and the " blue Lactarius " . In central Mexico , it is known as <unk> , <unk> , <unk> <unk> , <unk> , and <unk> ; it is also called <unk> ( meaning " blue " ) in Veracruz and Puebla . 
