Magnolias at the Brooklyn Botanic Garden

Spring has come early this year and the beautiful tulip-like petals of New York City’s magnolia trees are already beginning to fall into great drifts of white and pink.  If you stop and pick up one of the pretty petals from such a pile you will be surprised by the leathery resilience of the delicate-looking petals.  The durability of the petals of magnolia flowers is not coincidental—the flowers are different from other common flowering trees because Magnoliidae trees were among the first flowering trees to evolve.  The earliest known fossils of such flowers date from the upper Cretaceous period around 130 million years ago. Magnoliidae petals are tough because they were originally meant to attract the attention of beetles rather than bees (which do not appear in the fossil record until 100 million years ago).  Since there were no insects specially adapted to live as pollinators when magnolia-like trees first appeared, the petals and reproductive structures of these first flowering trees had to be robust to survive attention from the hungry clumsy beetles (toughness which has passed on to the modern ornamental trees).

Paeleobotanists have not yet unraveled the entire history of the evolution of flowering plants (indeed, Charles Darwin called the abrupt appearance of flowers in the fossil record “the abominable mystery”) however magnolia-like trees appeared long before the great radiation of angiosperms which occurred approximately 100 million years ago.  The first magnoliid trees must have seemed tremendously strange–explosions of color and shape surrounded by great uniformly green forests of gymnosperm trees (like the familiar conifers). Magnolia blossoms betray evidence of their ancient lineage through several “primitive” features: the petals are nearly indistinguishable from the sepals; each flower has many stamens which are arranged in spiral rows; there are multiple pistils; and all of the stamens and pistils are supported by a “fingerlike receptacle.”

By attracting the attention of animals (either through the colorful appearance and appealing scent of flowers, or by the edible nectar and fruit) flowering plants were better able to reproduce themselves.  Magnolias spread around the temperate world and began the complicated interdependent relationship which all sorts of animals (including humans) have with flowering plants.

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