logosmall.JPG (9291 bytes)

Vascular Flora of the Southeastern United States

J. W. Hardin, J. R. Massey, A. E. Radford, J. W. Thieret, eds.

Gymnosperms

Copyright - James W. Hardin, Ph. D., 1998, 1999. All Rights Reserved.

The Gymnosperms, with four of the 16 families and 12 of the 86 genera in the southeastern United States, are characterized as having "naked seeds," i.e., naked ovules at the time of pollination. This is in contrast with the Angiosperms which have the ovules enclosed in a carpel. Therefore, in the Gymnosperms, the pollen actually reaches the ovule at pollination whereas in the Angiosperms, the pollen stops at the stigma. Another difference it that in Gymnosperms the storage tissue of the seed is the pre-zygotic megagametophyte tissue whereas in Angiosperms it is the post-zygotic endosperm formed by double fertilization. Pollination is by wind except for the Zamiaceae which is primarily beetle pollinated. Hardin, J. W. 1971. Studies of the Southeastern United States Flora. II. The Gymnosperms. Jour. Elisha Mitchell Sci. Soc. 87:43-50.