This is a picture of one of the many Boxelder trees that we have along the back of our property. Notice the brown items, otherwise known as the Samara, which are essentially a type of fruit and covering most of these trees. They're much easier to spot now that they've dried and turned brown.
Samara's are often referred to as a wingnut, helicopter, whirlibird, whirligig, polynose, or, in the north of England, a spinning jenny. I like to refer to them as super annoyances for the fact that they're very mess this time of year when they begin to fall and fly all over the place. It's a bear keeping the pool clean of them.