Mine is all green with the white stripe, no purple at all.

Mine is green with a white stripe. Outstanding ornamental grass, by the way. Perhaps my favorite.

This is just my experience..but, for me, it depends on the weather...my "Adagio" all came up early this year and are all 2 foot tall now...our weather has been erratic, in the uppers 80's one week, frost the next week...after it was hot and then frosted, they turned a maroonish color, so this year, mine are green with a white stripe and have a purple tint to parts of the plants...

See link below for a photo that should help. The purple coloration of the foliage may be just as mentioned, an environmental influence. If they otherwise look alike they're probably the same plant. As you can see in the photo, it looks like some of the older foliage is purpleish, probably from cold or some other influence.

Another identifier will be the blooms -- they'll emerge late summer looking pinkish or salmon and gradually turn creamy white.

Here is a link that might be useful: {{gwi:859038}}

I knew you guys would be all over it! Carol_Ann, that photo is especially helpful. Thanks, all.

ianandsara, I found another picture, I hope it helps!

Here is a link that might be useful: {{gwi:859041}}