Practice question

Pteridophytes combine traits morphologically intermediate between bryophytes and spermatophytes illustrating evolutionary transition. Unlike non-vascular bryophytes lacking xylem lignification and true organs, they possess true tracheids with lignin, phloem sieve elements, enabling vertical growth and homoiohydry. Unlike gymnosperms and angiosperms forming seeds via heterospory plus integumented megasporangium and pollen, they remain seedless reproducing via free spores requiring external water for fertilization. Therefore botanical description as seedless vascular plants accurately captures vascular organization without seed habit, including ferns, horsetails, clubmosses and whisk ferns.