The strongly radially-corrugated, dark reddish brown pileus and pale greyish
orange membranous annulus are distinctive features of this lovely agaric.  It
apparently forms an ectotrophic relationship with black-wattle acacia (Acacia mearnsii
De Wild.) introduced into the Hawaiian Islands from Australia in 1911.  We have
found only one population of the species in a pure stand of black-wattle acacia at
Koke`e State Park on Kaua`i.  For a description of the species see Mycologia 88: 278-294,
1996.