Without a doubt, this is one of the most striking agarics seen anywhere. When fresh and moist, the intense blue color really stands out; even the latex is blue. Found throughout eastern North America, it is distributed south to southern Colombia where it is associated with Quercus humboldtii. Associates in Costa Rica include Q. seemannii, Q. copeyensis, Q. oocarpa, Q. oleoides, Q. corrugata and Q. costaricensis. There is a form (or perhaps a distinct taxon), found near Palo Verde in the northern Talamancas, that has narrow crowded lamellae, an azonate pileus and smaller stature (image at lower left). This Lactarius is another example of the North Temperate heritage of mycorrhizal agarics in neotropical oak forests.