Seed-Bearing Plants

• Both flowering and nonflowering species fall within the spermatophyte category of plant. A primary characteristic of spermatophytes lies in their seed-bearing abilities. The evolution of seed-bearing plants enabled water-based varieties to migrate and adapt within land-based soil environments. According to the Canadian Encyclopedia, seed-bearing plants fall within two categories: gymnosperms and angiosperms. Gymnosperms harbor the nonflowering seeds, while angiosperms harbor the flowering seeds. Physical differences in the reproductive structures of gymnosperms and angiosperms explain why one produces flowers and the other doesn’t.
  
  

Seed Types

• Flowering and nonflowering plants differ in how their seeds appear and reside on leaf surfaces. According to the University of California Museum of Paleontology, gymnosperms carry their seeds inside cone structures, though the actual seed portion remains exposed to the elements. Their seeds have no protective covering and remain this way until germination processes begin. Angiosperm seeds do have a protective covering that contains the nutrient materials needed for growth after fertilization takes place, according to the New World Encyclopedia.
  
  

Reproductive Structures

• According to the Canadian Encyclopedia, the cone structures found in nonflowering plants contain either male or female reproductive structures. With flowering plants, both male and female structures can reside within the flower of the plant, according to Kimball’s Biology Pages. Male structures appear as stamens, made up of a stem-like filament and a round-shaped anther on top. The female portions sit inside the carpel, which grows in between two leaves. Within the carpel sits the ovary sac, which houses the ovule or seedling. The ovary sac connects to a stem-like style structure topped off by the stigma. In effect, flowering plants can fertilize themselves or other plants.
  
  

Fertilization

• The different reproductive structures found in flowering and nonflowering plants affect how the fertilization process unfolds, according to the Oracle ThinkQuest Education Foundation. Both types of plants rely on pollen as a means for fertilization. The male stamen produces pollen grains, which must enter female ovary sacs in order for fertilization to take place. Once fertilized, the gymnosperm’s exposed seedling must find suitable soil conditions in order for a new plant to grow. The protective covering found on angiosperm seeds provides an added nutrient source, making them more viable within whatever soil environment they land.
  
  

Pollination

• According to the Oracle ThinkQuest Education Foundation, the vast difference in the number of species found among flowering and nonflowering plants results from the many routes of pollination flowering plants can use. Flowering angiosperms can produce bold colors and strong fragrances. These characteristics draw insects and animals to them. When an insect or animal brushes up against the flower, pollen grains can stick to them. In effect, a plant’s reproductive reach equals the distance that can be traveled by an insect or animal. As nonflowering plants have no flowers, they must rely on wind currents and rainfall to carry pollen grains to other plants.