Self-sterile A plant not capable of reproducing with its own pollen.
Semi-double A flower with only a few stamens converted to petals; a flower with less than twice the normal number of petals.
Muscadines come in self-fertile and self-sterile lines. The best fruits are from the self-sterile vines; to assure pollination you have to grow a pollinizing vine, too. Whether a variety is from a self-fertile line or not should be noted in the mail-order catalog or at the nursery.
Dogwood shrub flowers are self-sterile, so they must be cross-pollinated to produce seed. Seeds need cold stratification for one to three months in order to germinate; they will remain viable in cold storage for four to eight years.
Self-unfruitful or self-sterile
Plants in which very little fruit will set
Varieties that set fruit with their own pollen
Varieties that will not set fruit even when cross-pollinated
Neither of two varieties will fertilize the other ...
Many arugula varieties are self-sterile and need insects for cross pollination. They do not cross with other Brassicas, so you can save seed for planting next season.
Pests and Problems ...
Finally, you need to consider pollination - most apple trees are ~ and require the pollen from other apple trees in order to produce fruit. See the section on pollination for advice and guidance.
Note: There are two different kinds of muscadines: self-fertile types, which are self-pollinating, and ~ (female) types, which must be planted near self-fertile types to produce fruit. See "Editor's Homegrown Favorites" at above, right for two great picks.
See also: What is the meaning of Sterile, Plant, Planting, Growing, Trees?