What Agaricus is this ?

[Aruncus]

My  boss at work brought in some Agaricus from his yard in Wenatchee,
Washington.  The caps are approximately 4-6 cm. having some brown areas on the
surface.  Gills are pink when young, browning when mature,  spores are brown. 
The annulus is not distinct,  the veil is complete when young, and the cap  is
conical shaped.  They smell like  paste to me,  I  cooked some up and ate them
but they tasted like the paste we used in grade school a long time back.  He
has eaten them more than once, with no ill effects.    I have not noticed any
yellowing at the base of the stem or anywhere else, but  they seem to fit
Agaricus xanthodermus in many ways.  What do you think they are ??  Thanks,
Kevin