Practice question

Fossil evidence indicates Rhyniophyta alone comprised tracheophyte flora during late Silurian, approximately 430 to 420 million years ago, with Cooksonia as index genus from Welsh borderland deposits. Zosterophylls and basal lycophytes appeared near Silurian-Devonian boundary, while euphyllophytes, trimerophytes and progymnosperms expanded in Early Devonian. Later Devonian witnessed formation of first forests, Carboniferous dominated by arborescent lycopsids and ferns, Permian by seed plants. Silurian exclusivity therefore marks initial vascular plant radiation after divergence from charophyte algal ancestors. This structural framework illustrates phylogenetic relationships and adaptive significance highlighted in competitive examinations focusing on comparative plant morphology and systematics.