Mosaic Darner Dragonfly
I think this dragonfly is either a Green-striped Darner (Aeshna verticalis) or a Canada Darner (Aeshna canadensis). I captured this photo as this beautiful dragonfly hovered above the water feature at Distant Hill Gardens. It is most definitley from a group of dragonflies refered to as Moasic Darners.
Mosaic Darners are large, mainly northern dragonflies characterized by their intricate patterns of blue to green to yellow. They are very active fliers, rarely seen perched making them very difficult to ID in the field. They are best identified in the hand by details of the terminal appendages, with the shapes of the markings being generally more useful than the color.