Structural versus Functional genetics.Similar yet very different.To go any further would be a waste of typing do to lack of everything.
Botanically speaking you have a valid point as far as classification goes.I grow a lot of the triticum family myself.I harvest it during the vegatative stage of its life cycle.Thus I grow wheatgrass not wheat berries/fruit of the grass/triticum.
I grow grass from berries but do not grow berries from grass.