September 22, Mt. Holyoke Range State Park, Amherst
The infructescences on this plant were terminal, which is a feature of the native bittersweet. However, it was likely to represent a hybrid with Oriental bittersweet. Another critical character that helps distinquish between the native species and its hybrid with an alien (which may look much like the native species) is the number of ripe seed in each fruit. A bittersweet capsule generally is 3-locular, with 1-2 seed in each locule, so that the maximum number of seed is 6. Normally, American bittersweet may produce more ripe seed per fruit than this plant did. The seed count for a few of these capsules yielded a mixed result: from 1 to 6 ripe seed per capsule. Diminished number of seed is a condition that may well be pointing to hybridization.