Galium concinnum; Rubiaceae (madder family)
I post this with some trepidation, as I’m not sure that I got the species right. For sure it is a Galium of some sort. If you’re walking along in the shady woods and see little clouds of white dots seeming to float a foot or two above the ground, you’re probably looking at a bedstraw. This one has unusually tiny leaves. The flowers are about a sixteenth of an inch across.