Grass Seeds -- All are (technically) edible!

The seeds of all grasses are supposedly edible, as long as they are not fungally infected (beware of any black discoloration),  although only a few of them are actually worth your time spent gathering and processing them.  Collect them by bending the seedhead over into a bag and shaking them into it after they've turned yellow or brownish (mostly in late summer and early fall).  They are a good source of nutrition that stores well for winter and should not be neglected by the serious forager.   Also, certain types of tall grasses have tender, yummy inner parts just above each node ofthe stem that are good for trail snacking  (mostly in late spring and early summer). 
Also, it's good to know your Grasses from Sedges and Rushes. I learned a handy rhyme the other day which may prove useful:   Sedges have Edges,  Rushes are round,  and Grasses have Nodes all the way to the ground.  This rhyme refers to the shape of the stems.  Sedges have triangular stems, while Rushes are more circular.