The genus Magnolia includes about 225 species of trees and shrubs, many valued for their large, fragrant blossoms. While the flowers capture attention in the spring, the seeds offer a dramatic, visually distinct feature in the fall. The reproductive process of these ancient plants results in seeds that feature a complex structure. This striking appearance makes the seeds sought after for propagation and a unique visual element in the autumnal landscape.
How Magnolia Seeds Are Presented
The seeds are housed within a woody structure known as a follicetum, an aggregate fruit composed of multiple individual follicles. This structure is often described as cone-like due to its oblong or cylindrical shape, resembling a miniature pinecone. Initially, the fruit is green, but as it matures in late summer or early fall, it transitions to a brownish or reddish-brown hue.
The fruit signals the ripeness of the seeds by splitting open along the seams of the individual follicles. This dehiscence reveals the seeds nestled inside, which often hang visibly from the cone. Each seed remains attached to the inner wall of the follicle by a thin, white or reddish thread called a funiculus. This delicate suspension makes the bright seeds highly noticeable against the background of the opening, darkened fruit structure.
The Distinctive Fleshy Coating (Sarcotesta)
The most distinctive visual characteristic of a magnolia seed is its bright, fleshy outer layer, termed the sarcotesta. This coating presents in vibrant shades, most commonly bright red, scarlet, or orange-red, creating a bold contrast with the drying, brown fruit cone. The sarcotesta is a soft, pulpy, or waxy layer that is slightly oily to the touch.
This brightly colored layer serves a biological function, adapting the seeds for dispersal by animals, a process known as endozoochory. The striking color and edible nature of the sarcotesta attract birds and small mammals, which consume the seed and later excrete the hard inner part far from the parent tree. This outer coating is also known to contain chemical inhibitors that must be removed for the seed to successfully germinate.
Appearance of the True Seed
The true seed is revealed after removing the fleshy sarcotesta, typically by soaking and gently rubbing the seed. Once stripped, the seed’s permanent appearance is revealed: a hard, protective structure called the sclerotesta. This inner shell is generally dark brown or black, though it may appear tan or light gray depending on the species and how thoroughly the sarcotesta residue was cleaned.
The shape of the true seed is generally round, oblong, or kidney-shaped, often exhibiting a smooth or slightly pitted texture. At maturity, the seeds typically measure between 6 and 18 millimeters in length, varying significantly across the hundreds of Magnolia species. This hard, dark shell is durable, protecting the embryo and endosperm within until conditions are right for germination.