The southern magnolia (Magnolia grandiflora) is of an ancient lineage. Emblem of the old South, its roots reach back much further into the evolutionary past. In his marvelous book, A Natural History of Trees of Eastern and Central North America, Donald Culross Peattie wrote of how magnolias “have come down to us, by the winding ways of evolution, from an unimaginable antiquity.” Paleontologists have found fossils of past species of Magnoliaceae, the family of plants to which magnolias belong, stretching back 95 million years. Those earliest ancestors of the magnolias of today flourished during the mid-Cretaceous Era in the days of the dinosaurs, before Tyrannosaurus rex even appeared on the scene. A species of magnolia tree similar to magnolias of today has been identified from fossils dating back to twenty million years ago. Once spanning the globe, Ice Age glaciation extirpated magnolias from many places, leaving behind a disjunct distribution of species. Of the 245 species of trees and shrubs in Magnoliaceae, two-thirds are found in Asia, and forty percent of these are in southern China alone. The other third is found in eastern North America, the West Indies, Central America, and South America. Over half of these 245 species are now approaching extinction in the wild, due to rapid destruction of their forest habitat.
Denizen of the southern Coastal Plain and established guest across much of the southern Piedmont, the southern magnolia fortunately has a fairly secure future. It has become emblematic of the old South, and is commonly seen growing on the properties of antebellum plantation homes, as well as many a suburban front yard. This author visited an antebellum mansion, now a bed and breakfast, in eastern Georgia a few years ago. In the front yard were a pair of mighty magnolias with immense trunks. The same trees could be seen as slender saplings in a photograph of the house taken just prior to the Civil War.
To view a blossoming magnolia and breathe in its strong lemony fragrance is at once to connect with both the heritage of the South and another heritage that reaches back to the very evolutionary origins of the angiosperms, or flowering plants. While not the most primitive of flowers (botanists grant that status to water lilies), magnolias are not far behind. They evolved before bees did, so they rely instead upon beetles for pollination. This may seem unusual, but in fact, beetles actually pollinate an amazing eighty-eight percent of all the flowering plants around the world. As pollinators, beetles lack the delicate elegance of a hummingbird or butterfly. They tend to be quite messy, bumbling about and damaging flowers in the process, and sometimes defecating and leaving waste behind. For this reason, magnolias have very hardy flowers, with thick sepals and petals and tough carpels. They do not secrete nectar. Instead, they produce protein-rich pollen upon which the beetles feed.
A number of other features of the magnolia blossom indicate its ancient lineage. As Peatiie wrote of its close relative the mountain magnolia (Magnolia fraseri), “Its antiquity is visible in its flower structure, which is primitive, and so is that of the fruit and of the wood.” Although most flowering plants have blooms in which the petals and sepals (modified leaves that protect the flower bud) look quite different (often the sepals are green and the petals brightly colored), the petals and sepals of magnolia flowers are virtually identical. The are arranged in a simple whirl pattern. The flower also produces no complex structures for limiting flower access to certain species of pollinators or for controlling pollinator behavior. Magnolia flowers are also unusual for having many stamens (male flower parts) and pistils (female flower parts). The receptacle to which both are attached bears the stamens at its base and the pistils at the top.
After pollination, the flower loses its petals and sepals, and the aggregate fruit begins to develop. The follicles (former pistils) form a cone-like structure. In time, these follicles split, releasing dry, seeds with bright red fleshy coverings called arils. High in fat, these seeds provide excellent forage for many species of small mammals and birds in the autumn. The birds are particularly familiar visitors, since they are themselves the descendants of dinosaurs. Their own ancestors may well have walked among (or trampled down, or eaten) some of the earliest members of the magnolia family, tens of millions of years ago.
This article was originally published on June1, 2010.