Bio430
Gymnosperms represent the earliest extant seed plants and include the tallest, broadest, and oldest of living organisms. They are heterosporous, with tiny microgametophytes (pollen grains) developing just 2 sperm each. Megagametophytes are relatively large, but always enclosed in an integument (that becomes the seed coat) and always remain attached as an ovule/immature seed to the mother sporophyte plant until the seeds or cones are dispersed. Gymnosperms are mostly woody shrubs to trees, and sometimes vines. Seeds may be borne in cones, or on modified leaves/stems, but the micropyle is always exposed to the environment at the time of pollination.
Seed plants lacking flowers & fruits
GymnospermFamilies
