There are a few august prairies in southwestern Ontario to enjoy. The two I know best are Ojibway Prairie Provincial Nature Reserve in south Windsor, and even larger and more extensive prairies at Walpole Island First Nation (WIFN). The prairies around Ojibway are open to all for exploration and the city-owned nature centre across the road is definitely a must to visit. The prairies at Walpole are not open, however. Most occur on private property, are well away from the road, and permission must be obtained. I always go with someone from WIFN and even then, only when permission has been granted.
This next image was taken on a recent visit, and looking in the same direction as the previous image, albeit a little closer to the lone tree on the right. The purples of Dense Blazing-star stand out tall amidst the gradually increasing yellow of various species of goldenrods.
Prairie Dock is not listed on any SAR legislation, but is S2 (Imperilled). Its large very rough sandpapery leaves which look like a shovel, and tall single flowering stem are characteristic. Note: if you are out on a prairie and need toilet paper, do not be tempted to use the leaves of Prairie Dock!
It is small....the third image is several times life size. If you find it, the dark green centres of the individual flowers will separate it from other members of the Spiranthes genus.
Another plant with white flowers at this time of year is Grass-of-parnassus (Parnassia glauca). The fine green lines on each petal are noteworthy.