Ralph Lindberg
There is a reason Palm is "commonly" called a grass.
It's because it's a Monocot (Monocotyledon), which includes grasses, orchids, bananas, onions, etc. But not "trees" (other then Palms)

Yes both (most) trees and Palm are flowering plants (Angiosperms). But grass is more "closely" related to Palms then to a Eudicots (hardwood), Magnoliids (Magolia and relatives) or Conifers (softwood)