Bittersweet rust

Posted by Carson (Portland, United States) on 29 November 2007 in Cityscape & Urban.

American bittersweet, Celastrus scandens, is rapidly becoming rare and is now a protected species.

Oriental bittersweet, Celastrus orbiculatus, on the other hand, is an invasive, non-native species.

Though they seem to look identical, you can tell the difference between the two. American bittersweet has smooth stems, while the stems of Oriental bittersweet bear blunt thorns. According to About.com, "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."

The bittersweet vine photographed here appears to be American bittersweet.