This section is from the book "Harper's Guide To Wild Flowers", by Caroline A. Creevey. Also available from Amazon: Harper's Guide To Wild Flowers.
P. instititia - A shrub, much branched, thorny, 2 to 15 feet high. Leaves inversely ovate, rounded or narrowed at base, acute or obtuse at apex, serrate, softly downy beneath. Fruit, small, black, round, with a whitish bloom. Flowers appear before the leaves, in clusters, 2 or more in a cluster.
Massachusetts to New Jersey and Pennsylvania, in dry-soil, along roadsides and in waste places.
Choke Cherry P. virginiana. - Flowers and fruit, in close racemes at the ends of branches. The cherries are dark red, harsh, acid, with astringent taste. Leaves, alternate, large, pointed, finely serrate, thin, oval to oblong. Fruit ripe in July or August.
A shrub or small tree, generally 2 to 10 feet high. Bark grayish, the inner layers possessing an unpleasant odor. Banks of rivers, New England to Georgia.