RIC does not list this issue with palm branch XXI, though the previous issue (RIC 624) has the same mintmark
Maximianus
A.D. 285-290
Æ Antoninianus
21mm 3.9g
IMP C M AVR VAL MAXIMIANVS P F AVG; radiate & cuirassed bust right
IOVI CONSERVATORI AVGG; Emperor standing right receiving Victory from Jupiter standing left with long scepter; TR in center.
in ex. palm branch XXI
RIC V Tripolis 626