Montsechia, an ancient aquatic angiosperm

More than 1,000 Montsechia vidalii specimens from Barremian freshwater limestones preserve flexible leafy axes and closed single-seeded fruits; their morphology, thin cuticle, rare stomata and sedimentary context support a submerged freshwater habit without establishing the ecology of the angiosperm ancestor.

Angiospermae is treated as the flowering-plant clade; fossil placements and calibration densities remain analytical inputs rather than direct ancestor assignments.

Montsechia supports submerged freshwater ecology for that fossil only; the profile does not project aquatic habit onto the angiosperm ancestor.

Flowers, enclosed ovules and fruits diagnose angiosperm context, while the profiled Montsechia material preserves leafy axes and closed single-seeded fruits.