Unidentified plant - Milkvetch?

I never go out on local evening bird walks, as I am always too tired to walk for 2 1/2 - 3 hours (with lots of stopping and observing) by that time of the day. However, yesterday, 20 June 2017, my place was so uncomfortably hot that I just had to get out for a while.

Yesterday's walk was at Lafarge Meadows in Fish Creek Park. Some good birds were seen, though all of them were far, far away and no good for photos. I happened to notice this flower off the main road. I remember seeing it once before, and still don't know what it is. It was on quite a tall, thin stem. The closest I've come, is perhaps Milkvetch.

Just as we arrived back at the parking lot, a storm blew in - really, a dust storm! An interesting experience. So many days recently have been windy, which of course plays havoc with taking photos of birds and plants.