For procreation, most plants need assistance, so they make use of, ahem, sexual devices. Flowers, that is. Humans admire flowering plants for their beauty, but in truth a blossom is nothing more than a lure, designed to attract an intermediary to do the necessary work of moving pollen from anther to pistil. A flower isn't a sex organ per se, but it contains the pertinent parts. Kind of like a silk negligee.
Some flowers attract with scent, some with color.
Most offer nectar as an enticement to visitors and as a way to ensure repeat visits. A poorly pollinated raspberry will have many shrunken, dry drupelets. A melon blossom that doesn't attract enough pollinators may produce a melon that is small, lopsided, and not very sweet. Other plants aren't choosy. They'll do business with birds and bees, and also with wasps, beetles, rodents, and even humans if that's what it takes to move the pollen.