Astraeus hygrometricus have been given a number of colloquial names that allude to its hygroscopic behavior , including the " hygrometer earthstar " , the " hygroscopic earthstar " , the " barometer earthstar " , and the " water @-@ measure earthstar " . The resemblance to Geastrum species ( also known as true earthstars ) account for the common name " false earthstar " . The specific name is derived from the Greek words ὑγρός ( hygros ) " wet " and μέτρον ( metron ) " measure " . The German Mycological Society selected the species as their " Mushroom of the Year " in 2005 .