Size dominated the evolution of plants in the Carboniferous. With the origin of forests in the Late Devonian, tiering on land became very important. Standing tall above all the others were three of the most common Carboniferous forest builders:Cordaites, gymnosperms with straplike leaves;the lycophytes, including Sigillaria the seal trees and Lepidodendron the scale trees;and Calamites, belonging to the group of spenopsids. Calamites are known to have reached heights of up to 20 meters tall. Seems tall for a rush tree, but some lycophytes grew over 30 meters and some Cordaites grew to 35 meters.