They call them false tentacles on the oral disc. That is the only sure-fire way to tell the difference. Also, yumas are many time a more pastel color than the solid colors of the ricordea florida. Yes, R. floridas dual have multiple solors on occasion, but they are still usually solid and with distinct patterns. The last way to tell the difference is that many time R. florida will have multiple mouths on a single polyp and many times become odd shapes, whereas R. yuma will usually only have one mouth and be in a regular round shape.
Also, saying a yuma from regular ricordea is deceiving, because yumas are as regular as the R. florida, it's just that R. florida are close and this makes them much more accessable to us here in the states.