Ice ribbons also referred to as frost flowers, form when liquid water inside a stem seeps out into the open air and...

Ice ribbons also referred to as frost flowers, form when liquid water inside a stem seeps out into the open air and freezes. Capillary action inside the plant pumps more water out so a continuous stream of ice is formed.

know more:http://en.wikipedia.org/wiki/Frost_flower
Photo Credit: Dr. James R. Carter