Yes, this is an agaric, albeit it has lost hymenophoral organization and the ability
to forcibly discharge its basidiospores and become "secotioid."  Although considered by
many to be a stalked puffball, Podaxis pistillaris  is more closely allied with the shaggy
mane (Coprinus comatus  (Mull.:Fr.) S. F. Gray) than with puffballs (see Hopple &
Vilgalys, Mycologia 86: 96-107, 1994).  In the Hawaiian Islands, it is frequently
encountered along roadsides and in disturbed areas on the dry sides of the islands,
especially in the Kona area of Hawai`i and the Kihei area of Maui.