it is
Nopalea cochenillifera (L.) Salm.-Dyck. Cact. Hort. ed. 2, 64, 1850;
Almeida, Fl. Mah. 2: 336, 1998; Singh et al, Fl. Mah. St. 2: 83, 2001.
Synonyms: Cactus cochenillifera L., Sp. Pl. 468, 1753. Opuntia
cochenillifera Mill., Gard. Dict. ed. 8, 6, 1768.
here is the distinguishing character for the two genera
Stem flattened, not winged
3. Stamens exserted beyond corolla..........................Nopalea
3. Stamens not exserted beyond corolla....................Opuntia
regards
satish pardeshi