Roadside flowers

I really like these flowers, but have no idea what they are called. They appear to close up almost totally at night and reopen during the day. Insects love them and are always buzzing around or sitting on them.

There is one spider in particular that sits right in the flower, is perfectly camouflaged, and waits for bees to visit, then attacks them and takes them round the back of the flower to eat. I've seen it happen several times but have always been camera-less.