The equisetales attained their evolutionary zenith in the later Paleozoic Era more than 300 million years ago -- long before dinosaurs appeared. Some grew into trees. Today, only about 2 dozen species remain, most growing like rushes in moist areas. Because their stems are rich in silica, they were crumpled and used as scouring pads in earlier times.
(Photos were taken in Kanapaha Botanical Gardens.)
