This native wild edible, known as corn salad or mâché is fairly common in this area, but will disappear as the days get hotter and longer. One of the key identifying features is the erect stem with opposite branching that you can see in the picture. It has tiny white flowers with five petals and three stamens each.
It has a fairly mild and herbaceous flavor that we enjoy as an addition to mixed green salads this time of year.
One of the fun aspects of eating wild foods is the opportunity to eat from a much wider range of plant families than is available at the supermarket, and this Valerianaceae member certainly fits that bill! It is related to the medicinal plant Valerian, but does not have the same properties.