Ligature of the letters Alpha and Rho.: Ligature of Alpha and Rho.
Reference
Lang, M. and M. Crosby (1964). The Athenian Agora X: Weights, Measures and Tokens. Princeton, New Jersey, The American School of Classical Studies at Athens. (https://zenon.dainst.org/Record/000211771)
The Genius Populi Romani standing left holding patera in right hand and cornucopia in left, behind him Roma stands left holding shield in right hand and spear in left.
Reference
Rostowzew, M. (1903). Tesserarum urbis romae et suburbi. St. Petersburg., https://zenon.dainst.org/Record/000917434