Rubus occidentalis L.
The cultivated Black Raspberry is Rubus occidentalis, an American species, and is not the same as the Red Raspberry (Rubus idaeus).
Info below is from /www.cnr.vt.edu.
Leaf: Alternate, palmately compound, 3 to 5 leaflets with serrated margins, small prickles on petiole, light green above, paler below.
Flower: Greenish, small white petals, appearing in May, not showy.
Fruit: Juicy, black, multiple of drupes. When picked they separate from the fleshy core forming a hollow shell. Ripen in June to July.
Twig: Arching "canes" which generally live 2 years. Purplish-red with an abundance of white glaucous bloom and hooked prickles. Canes readily root at the tips when they contact the ground.
Form: Arching canes may reach 4 to 6 feet high, often forming tangles.
Black raspberries look much like blackberries, though black raspberries taste more like and are hollow like red raspberries.