I have white oak floors and I was pretty surprised by the wild patterns and wide variation when I first saw them.

As my floors aged and sunlight changed their color, the patterns and stripey-ness got substantially toned down. They now look much more uniform than they did at initial install. Every time I pull up one of my area rugs I'm so surprised at what they look like under there....

There are different grades of hard wood, with cost differences between them. Clear is highest with Select next. You may have ordered Common grade, which shows more variation. I think they look beautiful and natural!

https://theflooringblog.com/different-grades-of-hardwood/

"Every time I pull up one of my area rugs I'm so surprised at what they look like under there...."

I get that same result when I look in a mirror. Solid wood floors usually age well, I am trying to do the same.

Those water marks on boards in the first picture are unusual but I have seen them before. Since your floor is obviously a rustic grade, I see nothing unusual otherwise and I don't find the water marked boards unacceptable. If your floor was select or clear I might fuss about them.

Water marks are normal and common throughout all grades and cuts.

Thanks everyone!

Beautiful floors!