One suggestion is Kalmia latifolia, but I suspect it is not. Four-foot shrub growing in very wet are adjacent to a pond in central NH. I will explore tentative identifications.
Fairly certain it is a member of the Ericaceae. How about Lyonia ligustrina http://vascularflora.appstate.edu/s...nia_ligustrina_(L.)_DC._var._ligustrina_1.jpg instead?
That's it! It's rather uncommon in this immediate area, but I now recall the blueberry-like blooms, and the ID is 100% certain. Thank you!