This variety was not documented in Riddell (1845), but other 'Floating Cactus' varieties from this same counterfeit family were listed there.  The Floating Cactus refers to disconnected cactus on the right side of the reverse below the eagle.  I believe this piece was struck on a German silver planchet.

1836 Zs 8 reales counterfeit 'Floating Cactus'