Tall Oatgrass (Arrhenatherum elatius) -- not quite discouraging.
The good news: The North American "Research Grade" observations of Arrhenatherum elatius were nearly all correct! (Or too distant to identify with certainty -- oh, well). The bad news: There were almost three times as many "Needs ID" observations of this species, and at least half of them were clearly not A. elatius while many of the rest were not really identifiable to species. So the filter of needing two agreeing ID's to reach "Research Grade" is working (good news!).
Arrhenatherum elatius is an almost generic grass, so misidentifications were not unexpected. The breadth of misidentification did exceed my expectations, though. (Four different Lolium perenne observations??) The misidentifications didn't have a unifying theme, as did those of Phleum pratense.
Here's a list of names I found on North American "Needs ID" Arrhenatherum elatius observations today:
Anthoxanthum odoratum
Avena sativa
Bromus inermis
Bromus sp. (weedy annual; B. japonicus?)
Dactylis glomerata (in early bud)
Danthonia sp.
Festuca sp.
Leymus mollis
Lolium/Festuca/Schedonorus arundinaca (many, many observations)
Lolium perenne (at least 4!)
Phalaris arundinacea
Poa pratensis
Stipeae
Triticeae (at least 2 species)
and something lily-like, with wide, soft leaves
