sheepberry

from The Century Dictionary.

• noun A small tree, Viburnum Lentago, of eastern North America. It bears small white flowers in cymes, and black edible drupes.
• noun The fruit of the above tree, so called from its fancied resemblance to sheep-droppings. Also nanny-berry.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) The edible fruit of a small North American tree of the genus Viburnum (V. Lentago), having white flowers in flat cymes; also, the tree itself. Called also nannyberry.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The plant Viburnum lentago, native to the northeastern and midwestern United States and southern Canada.
• noun Its edible fruit.