Our orange-red fruited mystery seeds from last week were from a bittersweet plant, Celastrus sp.
Bittersweet grows as a vine that creeps up trees. It isn't noticeable in the summer, but in the fall the bright orange berries seem to appear out of nowhere.
There are two species of bittersweet that occur in eastern North America.
The American bittersweet, Celastrus scandens, is an indigenous plant that is not harmful to the trees it uses as support. In contrast, the oriental bittersweet, Celastrus orbiculatus, is introduced from Asia and is considered to be an invasive weed.
Because the fruit capsule is deep orange rather than yellow and because the plant lacked thorns, I believe the plant in these photographs to be Celastrus scandens. The two species are known to hybridize, however, so I can not be certain.
Bittersweet is often used in fall floral displays.
Have you ever seen bittersweet growing where you live?