hmm..there are fields of the stuff around here, it's literally everywhere.
You could check around farmers fields..but that stuff might be low alkaoid because lot's of it was selectivily bred to contain low alks becasue of sheep staggers...
There are other species of phalaris as well..some even better than arundiancea..depending on where you live...
Wish I could help more..if you do find anything you could take pics and post it here for identification...not promising that it could be identified by pics but it's worth a shot I guess...
best of luck..
Long live the unwoke.