Practice question

Homosporous taxa, considered ancestral reproductive strategy in pteridophytes, release single spore type morphologically uniform in size, shape and function. Each haploid spore germinates into free-living, typically photosynthetic, cordate or subterranean mycoheterotrophic bisexual gametophyte bearing both antheridia and archegonia, often promoting intragametophytic selfing under favorable moisture. Lycopodium, Equisetum, and most Polypodiales exemplify this strategy with exosporic gametophytes. Heterosporous taxa produce differentiated microspores and megaspores yielding unisexual reduced gametophytes, marking derived condition leading toward seed habit. This structural framework illustrates phylogenetic relationships and adaptive significance highlighted in competitive examinations focusing on comparative plant morphology and systematics.