a widespread rot caused by the honey mushroom, Armillariella mellea, seriously damaging to the roots of various hardwoods, conifers, and other trees
Word origin
[‹ NL Armillaria an earlier name for the genus, equiv. to L armill(a) bracelet (referring to the braceletlike frill on such mushrooms; see armillary) + -aria, fem. of -arius-ary]