This time period took place 359 to 299 million years ago. 3 min read The Carboniferous ... with strap-shaped leaves. Over millions of years, the organic deposits of this plant debris formed ...

Clubmosses, as the earliest vascular plant group, have leaves with only a single vein of xylem down the middle, in contrast to the more complexly veined leaves of trees and even ferns. Nevertheless, ...