Name for ashes on ash Wednesday?

I'm leaving the original answer below the hyphens, but it's worth noting that Ash Wednesday does not have biblical origins. Ash Wednesday, like many Christian traditions practiced in the U.S. and...

Ash and sackcloth were used by the Jews as a sign of serious repentence, and the christians applied ash on their foreheads on ash Wednesday.

Burnt Palm Leaves

The ashes are burnt from the palms of the past year's Palm Sunday and they represent the sin that we have and the death that we will face (as in "for dust thou art and unto dust thou shalt return"...

The burn the palms that were used at the Palm Sunday Mass the previous year to get the ashes for Ash Wednesday.