Thank you for the response! I did figure it out as well, once I realized that the flower closes up in the cold, and found a few similar shots. But thanks again...

Native to nearly all of the eastern halves of the the US and Canada, plus Washington and Oregon. http://plants.usda.gov/core/profile?symbol=SPTO2&mapType=nativity More info: http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=e412 This post was edited by missingtheobvious on Sat, Jul 19, 14 at 0:10

Pity we can't see the leaves. But it could be Mentha aquatica, Water Mint, an introduced species. (btw some websites have incorrect pictures. 'Canada plants' shows Cardamine pratensis as Mentha aquatica.) Sadly being on a nature reserve is not a guarantee that a plant is native. Here is a link that might be useful: Water mint in Canada

Hi I've found the downside lol They sprout in every conceivable place Most amazing in a 1/4 inch crack between the house and patio In fact they grow best there lol There is also a form that has black in the center as well as a paler yellow variety The one with the black eye is very striking though not nearly as hardy as the normal type naturally. lol gary