We seldom give plant sex much consideration, but some species of flowering plants produce flowers with both male and female reproductive structures in the same flower (perfect flowers). Most of the plants you are familiar with are in that category. Other species produce separate male and female flowers on the same plant. The tassels on corn, for example, are male flowers while the female flowers develop into the ear of corn. Those plants are said to be monoecious. Dioecious plants are those species that produce male and female reproductive structures on separate plants. As such, a plant of these species is either a male or female plant, and only the female plants produce fruits and seeds.
Many of the trees across the state will soon be producing flowers. Many of these trees produce small, drab wind pollinated flowers that seldom catch our attention. And because they are wind pollinated, they flower before the tree has fully leafed-out, which of course would block the wind. Some observers will look up at these trees and declare that they are leafing out, but actually it is probably the flowers that are noticeable up there. Leafing out will come later.
But as the fruits and seeds start to develop from the female flowers, they become quite noticeable. And here is where things can be a bit confusing. Occasionally a person will question why one cottonwood tree seems to always produce copious amounts of “cotton” in the early summer while another cottonwood tree never does. The tree that produces the cotton is a female tree. There is a seed within each of those little puffs of “cotton.” Male trees just produce male flowers with pollen.
It is similar with green ash. Some of you may have noticed that some green ash trees always produce seeds (actually a fruit called a samara that contains a seed). Those are female trees. If a green ash tree never produces fruits, it is likely a male tree. Other common tree species with separate male and female plants include boxelder, quaking aspen, balsam poplar, and the willows.
It is not just trees that may have separate sexes. For example, buffalograss (Bouteloua dactyloides, Buchoe dactyloides), a grass particularly common in the western part of the state also has separate male and female plants.
As that old saying goes, “it takes two to tango.” That is true for all plants. But it is particularly challenging when the sex of a particular plant is either male or female. For the next generation to be produced their needs to be a male and female plant within some critical distance.
