It appears to be an iris, looks to be a beardless one, probably a
Louisiana iris that someone had planted in their yard and that got away
in a flood or by birds. Very common around SW Louisiana where I live and
I just pulled out a 33 gallon garbage bag of them along my driveway.

George

wrote:
http://oxholmfamily.com/geoff/poconoPictures/flower.jpg
Found in a marsh in the Pocono Mountains, Pennsylvania. Thanks!
(Link will go dead after identification.)