Peffley: Magnolia one of most primitive seed-bearing plants

As daylengths shorten, nights get cooler, and winds swirl leaf drop from trees is accelerating. Leaves of evergreens, however, persist throughout the winter.

One of the few broadleaf evergreens is the magnolia. The most commonly grown is the Southern Magnolia (Magnolia grandiflora), native to southeastern U.S.

Southern Magnolias are large, stately trees reaching a mature height up to 60 feet with a 40-foot canopy. With their thick, dark green leaves, oval in shape and glossy, waxy sheen, Southern Magnolias form a dense dark green pyramidal shape.

In the landscape magnolias are effective as solitary specimens or grouped. Their evergreen dark green foliage persists throughout the year providing winter interest, while their large, showy, fragrant blossoms are appealing in the summer.

The magnolia family, Magnoliaceae, is one of the most primitive of all living angiosperms (seed-bearing plants) dating back beyond 95 million to about 130 million years ago (Evolution and Classification of Flowering Plants, Cronquist 1988).

Magnolia fossils have been dated to between 36 and 58 million years, making this one of the oldest angiosperms still living. The magnolia has been dated to this age because it exhibits primitive characteristics, all of which involve its reproductive (flowering and fruiting) system.

The fossil records provide evidence that the primitive blooms of magnolia have changed little since their ancient beginnings. One characteristic of primitive plants is the magnolia flower. The large, saucer-shaped fragrant blooms have petals that are fused with other flower parts to form thick, showy structures called tepals.

The male parts of the flower that produce pollen are arranged at the base of the female part that contains the ovary. When the ovary is mature, it will form the fruit. Once pollination has taken place, the male pollen-bearing bodies fall away, revealing a cone-like ovary where seeds will develop, a second characteristic of primitive angiosperms.

Beetles are the vectors for pollination, a third characteristic of primitive flowering plants. Beetles are attracted by the pungent fragrance of the flowers, where rather than seeking nectar, high-protein pollen that is positioned to ensure beetles must crawl across the male to reach female parts of the flower.

The formation of tepals is significant because the tepals of the magnolia flower are tough enough to prevent damage from munching beetles.

The bizarre-appearing fruit that results from the development of the maturing ovary following pollination resembles a cone but is botanically a dry aggregate fruit (think an inside out pomegranate). The image in the photo is a mature ovary, the fruit, of the Southern Magnolia.

Male parts that were initially on the far end have been shed and are no longer visible. The female part contained the developing seeds, most of which have now tumbled out of their protective encasements but several red seeds remain in the fruit. Seeds attach to the fruit by stringy thin threads like parachute strings; a few remnants are still visible.

The Lubbock Memorial Arboretum, 4111 University Ave, has a grouping of three Southern Magnolia trees that still have their fruits attached.

Some information from the U.S. Arboretum

ELLEN PEFFLEY taught horticulture at the college level for 28 years, 25 of those at Texas Tech, during which time she developed two onion varieties. She is now the sole proprietor of From the Garden, a market garden farmette. You can email her at gardens@suddenlink.net.