Euonymus, maybe Euonymus europaeus, which although called European euonymus, is listed in a book called Landscaping with Native Plants of Minnesota, which came up on google books. The other one that came up is E. atropurpurea, which in one photo I found had leaves that didn't seem as good a match, though I'm not totally convinced about the leaves for either of these species. Most of the photos that come up for E. europaeus show red fruit capsules, but there are several photos that show white fruit capsules, which is what I think you're showing here; one is called E. europaeus 'Alba'. I'm not sure when you say "Minnesota tree" whether you mean you found it in the woods or if it might be in a landscaped area in your state. Maybe you could show a photo of the tree, and the trunk and branches. Are some of the branches corky?
Looks like the flowers haven't opened in the photo, fruit may be reddish orange in the fall with a red calyx.
The tree is in a landscaped area as seen in the background of image three. The correspondent said the photo shows unopened flower buds but I suspect it shows four-lobed seed capsules instead. Euonymus sp. is sufficient. Thank you Wendy and Chimera.
No, the first photo's named "image 3." I think the tree in the background is the tree in question. Could it be Euonymus bungeanus? Compare bark, etc. here: UFEI - SelecTree: A Tree Selection Guide
I'm not sure it could be. The page you've linked to lists that as USDA Hardiness Zones 5 - 8, whereas Minnesota has only a tiny sliver in zone 5, with the rest being in zones 3 and 4, see Big Changes for Minnesota in New Hardiness Zone Map. Well another page, Winterberry euonymus - Madison Gas and Electric - Madison, Wisconsin, shows hardy to zone 4a. Yet another shows hardy to zone 3. All right, ignore that. I'm not sure about the leaf shape. Your photos show the leaves widest toward the tip, and not very pointy tips, some leaves even no tips. Leaf photos on the page you've linked to show leaves widest toward the stem, and all sites mention the pointy leaf tips, but the last page I mentioned does say fruits yellowish white to pinky white. The leaf shape seems to match E. alatus, and it does have bark like that, but it is supposed to be shrubby and your tree has much larger leaves more widely spaced. Now I've just read this, about Wahoo, E. atropurpureus, fruits : "Their colors changed from white to pink to a brilliant fuchsia over the next 4-6 weeks ...". That's from gardening with turtles: Red, white...and wahoo!. So maybe they all do that? I don' t know how much variation there can be. There is certainly plenty of variation in the descriptions. I know I'm not answering your question. Glad you were happy enough with knowing the genus. Well, wait, I'll propose Euonymus hamiltonianus, which seems to have lots of cultivars, is hardy to zone 4. Leaf size and shape seem ok (in some but not all photos), including their having some leaves with pointed tips and some without. Some cultivars are shown with white fruit capsules. Canada Plants
