So, after wondering about evolution of words meanings and issues about gender and sex, I may post a very basic summary of how botanists happen to characterize sex in their study species. There’s indeed many levels, from flower to population, and sex (reproductive organs arrangement) and gender (relative investment into male and female functions) vary all along these lines. Yep, this is just a simplified view of sex classification in plants… Real world observations sometimes drive you into some more mitigated path.
So let’s see first about the most basic level in flowering plant reproductive structure, i.e. at the flower level:
|Pistillate||With functional pistil and fertile ovules||Female function only (sometimes called “male-sterile”)|
|Staminate||With stamen containing viable pollen grains||Male function only|
|Perfect||With both female and male functions||Hermaphroditic flower|
Sometimes either stamen or pistils are present at a vestigial (and non-functional) stage.There are also various intermediate stages, notably for stamens, the full characterization of which is often a tedious task, for example when pollen number, or when pollen viability varies, etc.
Now, we can move on the distribution of these different flowers in the individual plant:
|Female||With pistillate flowers|
|Male||With staminate flowers|
|Monoecious||With both female and male flowers|
|Gynomonoecious||With both female and perfect flowers|
|Andromonoecious||With both male and perfect flowers|
|Hermaphrodite||With perfect flowers|
|Trioecious||With perfect, female and male flowers|
There are numerous ways plant sex can depart from hermaphroditism, even if such a sex determination is not directly inherited as an ancestral state. Most surprisingly, any situation can be reached by both a slow graduation or an abrupt appearance, depending on the kind of mutation giving rise to those phenotypes.
Some mutations involving cytoplasmically inherited elements such as mitochondria are known to produce immediate male-sterility, for example. All of this can vary from one population to the other, and usually such a variation is the rule. Female sterility, on the other hand, is something somewhat rarer but does happen from time to time.
Please note that female function is also complex, because some flowers may produce typical female structures (from ovary to stigma) without actually being able to mature fruits and seeds, even when living in a rich environment.
OK. So now, we can safely take a look as to how those different plants are occuring at the population or the species level. Here is what happens in relatively simple situations:
|Monoecious||With monoecious plants||Zea mays, the Corn|
|Dioecious||With both female and male plants||Cannabis sativa, the Hemp (usually students know about this one)|
|Gynomonoecious||With both female and hermaphrodite individuals||Fragaria virginiana (I really don’t see why it’s the first example that comes to my mind… ;)|
|Andromonoecious||With both male and hermaphrodite individuals||Solanum carolinense|
|Hermaphrodite||With hermaphroditic individuals||Fragaria vesca, the Common Strawberry, among so many others…|
|Trioecious||With perfect, female and male individuals||Fraxinus excelsior, the European Ash. Actually, it’s even more diverse and would also fit into the next two lines of the table, depending on population under drift influence.Anyway in this case we are confronted to a species that’s undecided yet, and this situation is sometimes called polygamous. This last term is nevertheless not a good choice because of the confusion with the common meaning of polygamous (which characterizes most flowering plants species by the way).|
|Gynomonoecious-gynodioecious||With female, gynomonoecious and hermaphroditic individuals|
|Andromonoecious-androdioecious||With male, andromonoecious and hermaphroditic individuals|
I guess you now have a new game with your kids for the next walk through the meadow…