M>0.5. From a tree.

Wikipedia on the White Mulberry tree:

The White Mulberry is scientifically notable for the rapid plant movement of the pollen release from its catkins. The flowers fire pollen into the air by rapidly (25 µs) releasing stored elastic energy in the stamens. The resulting movement is in excess of half the speed of sound, making it the fastest known movement in the plant kingdom.

Outrun by a tree. Oh, the shame.