Plants have sex. While flowers, cones, and fruits– basically the vaginas and uteruses of the plant world– feature prominently in human cultures, much of the actual, er, act of plant sex is invisible to us. As northerners dig out from under record-breaking snowfalls and eye the ground for the first crocuses and robins, folks to the south are already beginning to experience a trademark of spring (and the male equivalent in the sex lives of plants): pollen season. The microscopic powder produced by seed-bearing plants are not sperm, per se, but are in fact microgametophytes, or sperm-producing cells. The word “microgametophyte” packs a handy definition for those up on their ancient Greek: “micro” means tiny, “gamete” is a combination of “husband” and “wife,” and “-phyte” refers to anything plant-related. Basically, pollen is a sperm delivery system. If a pollen grain “gets lucky,” that is, it meets the flowers or cones of its…