Practice question

Most extant ferns belonging to Polypodidae and core leptosporangiate clade are leptosporangiate, originating from single superficial initial cell undergoing precise periclinal and anticlinal divisions producing small stalked sporangium with distinct annulus, stomium and limited spore number typically 64 or 128. Primitive ferns like Ophioglossales and Marattiales are eusporangiate with larger thicker-walled sporangia from multiple initials. Leptosporangiate development enables massive spore production per frond, synchronized maturation, and explosive catapult dispersal, representing derived trait linked to diversification of modern fern families in Mesozoic.