Cannot speak for America buI I believe the only source of black pollen in 
Europe is the common field poppy, papaver rhoeas.  Before the days of
blanket spraying this was a common and attractive weed on all arable land 
but is not so common today, at least in my part of the world, southern
England.  Its relative, the oriental poppy, comes close to it in colour
with a very dark blue.                          Sid P.