The best of a nasty one. To quote another web site;
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"There are two dioecious vines with yellow and orange berries commonly
called "bittersweet." They look very much alike. One, an innocuous
vine indigenous to North America with smooth stems, is Celastrus
scandens, also called "American bittersweet" plant or "false
bittersweet." The other, an exotic vine that is among North America's
most invasive plants and whose stem bears blunt thorns, is Celastrus
orbiculatus, or "oriental bittersweet" vine. Another way to
distinguish between American bittersweet and oriental bittersweet is
by discerning the location of their berries: the berries of American
bittersweet plants appear at the tips of the vines only, while those
of oriental bittersweet vines grow along the vine. But the biggest
distinction between the two is in terms of their environmental impact.
For while oriental bittersweet vines are considered an environmental
menace by many, American bittersweet plant is becoming so rare in some
areas that it is now a protected species. It is the oriental
bittersweet vines that threaten to kill your trees; while American
bittersweet plants are themselves threatened."
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By this description, the berry location along the vine makes this the
oriental variety. It is a real P-i-t-A, and I spend a lot of time each
spring trying to keep it under control along our wooded boundary. It
can be pretty at this time of year, however.

JD