 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 añil , azul , hongo azul , zuin , and zuine ; it is also called quexque ( meaning " blue " ) in Veracruz and Puebla . 
