Gymnosperms

In contrast to most Angiosperms, Gymnosperms (from Greek, gym means “naked” and sperm means “seed”) do not have flowers. Gymnosperms are plants that produce their seeds in cones. 

• The seeds in gymnosperms (as shown below, left) are “naked.” This means that, unlike the seeds of angiosperms, the seeds are not surrounded by an ovary (which later develops into fruit). An angiosperm seed — which develops from the ovule — is shown below, right. Unlike the gymnosperm seed, it is surrounded by the ovary/fruit.

• The seeds in pine trees are wedged between the woody “scales” of the cones. The picture below (left) shows a pine cone and some seeds from the pine cone (to the right of the cone). As shown below (on right), pine seeds may have "wings," which help them to move father away from the tree where they were "born."
  
  
  

  

Conifers are (by far) the most common type of gymnosperm. Conifers are woody plants with needles (as shown in the picture above).  Conifers include: cedars, firs, cypresses, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews.

    

Life Cycle of Gymnosperms. A mature gymnosperm tree generally has both female and male cones.

What we call pine cones (shown in the pictures below) are the tree's female reproductive organs. In a mature pine cone, egg cells are formed at the base of the scaly leaf-like structures (near the center of the cone). (The pinkish areas in the middle picture below show about where the eggs are.)

Gymnosperms also have male pollen-producing organs (pollen cones, shown below), which are soft and form in clusters. The male cones are in general located lower on the tree than female cones. This makes it more likely that the wind blows pollen to different trees, fertilizing their eggs. (This is a good thing because it causes genetic diversity.) Pollen that lands near an egg between the scaly leaves of a mature female pine cone will form a tunnel to the center of the egg and fertilize it.

Fertilized eggs become seeds, which contain a plant embryo. Some time later, the scaly leaves of the pine cones open up and the seeds are blown away by the wind, where (if lucky) they will grow into trees.