Myrmecodia lamii

Myrmecodia lamii is a myrmecophilous (Ant loving) plant in the Gardenia Family (Rubiaceae) and native to New Guinea, with a greatly swollen hypocotyl region containing numerous tunnels and chambers utilized by certain species of ants as a colony. This hypocotyl can measure up to 70 centimeters (27.5 inches) in height by  up to 45 cm ( 17.75 inches) in width; by far the largest known hypocotyl.