Not exactly meadowsweet
This woodland wildflower, blooming in early June in Nichols Arboretum (Ann Arbor) remains a mystery to me. The plant whose blooms these most resemble in my wildflower guides is meadowsweet, Spiraea latifolia, but the leaves are lobed, which is wrong for that species. The bloom clusters do have the general appearance of a spiraea, but for me, the jury is still out…