Some would say the first plant: ever! A gigantic earlier relative of the common horsetail thrived in the Carboniferous era and eventually became our present day coal deposits. Containing silica, horsetails make a natural "sandpaper." On the west coast horsetails and salmon slime were used to polish masks, canoes, bone tools and soapstone pipes. In spite of the rough texture of the stalk, the young plant heads can be eaten as asparagus.