— Nan Sterman
Sex is complicated in the plant world. Flowers have male and female parts; some have both, some have one or the other. A male flower part is called a “stamen,” that’s
where the pollen is. Pollen is the plant world equivalent of sperm. The female flower part is called the “pistil.” The base of each pistil is an ovary.
In the simplest terms, flowers get fertilized when pollen reaches the ovary. That starts the process of the flower transforming into a fruit, inside of which are seeds that make the next generation of plants.
The swelling at the base of the pomegranate flower is the beginning of a pomegranate fruit.
If you grow squash, you’ve probably seen this process though you might not recognize it. Squash plants make separate male flowers and female flowers but both grow on every plant. The female flowers have a slight swelling at the base of the petals. That swelling is their ovary. When pollen from the male flower fertilizes the female flower, the ovary begins to develop into the “fruit” we know as squash.
Since a fly or a bee can pick up pollen from a single male squash flower and move it to many female squash flowers, for vegetable gardening purposes, just a few male flowers can service many females (no jokes please). Since the male flower doesn’t have an ovary, it can’t form a squash. That’s why we harvest the male flowers to make stuffed squash blossoms.
The male/female distinction may be confusing to us but it’s not to pollinators. They visit flower after flower in search of sweet nectar and/or pollen, both important food sources for pollinators and their offspring. While they move pollen from flower to flower by happenstance, pollinators do the critical work that produces about a third of the fruits and vegetables we eat.
Who’s a pollinator?
Honeybees are the pollinators we hear about most often. They pollenate everything from oranges to almonds, watermelon to blueberries. And in the process, they produce honey we use to sweeten tea, baked goods, and other yummy things.
As important as honeybees are, most are European imports, brought to America about 400 years ago and naturalized across the continent.
European honeybees are just one kind of bee pollinator. California is home to 16,000 species of native bees like native digger bees, bumble bees, mason bees and others that also move pollen from one flower to the next.
Butterflies and moths pollinate flowers too, as do hummingbirds, bats, and even the common houseflies.
Watch for part II, next week
Common house flies hard at work pollenating radishes
