Why are lower vascular plants useful for studying plant evolution?

Lower vascular plants—which include ferns, club mosses, spike mosses, quillworts, horsetails, and whisk ferns—are invaluable to researchers studying plant evolution for several key reasons:12

• Evolutionary Insight: Because they possess relatively simple structures and life cycles, these plants provide a clear window into the early development of plant body plans, including the transition to terrestrial life and the emergence of vascular tissue.1
• Fossil Record: As some of the oldest land plants, their remains—which form the bulk of the world’s coal beds—offer extensive data on evolutionary trends, such as the development of roots, stems, and leaves, as well as the independent evolution of secondary growth.134
• Comparative Biology: By studying both extinct and extant forms, botanists can trace the shift from homosporous life cycles to the more complex heterosporous systems that eventually paved the way for seed plants.35

Ultimately, these plants serve as a vital link in understanding the structural and reproductive innovations that allowed tracheophytes to become the dominant terrestrial organisms.12