May 25, 2018
The spring wildflower season of 2018 pales in comparison to the extraordinary Southern California super bloom of 2017. Nonetheless, throughout Los Angeles County this spring, poppies are blooming (just not by the millions). In gardens, native hillsides, urban parks, and along freeway medians are two poppy species native to California: the small and golden California poppy and the large and regal “sunny side up egg” poppy, known as Coulter's Matilija poppy.
Fascinating and unseen within these native California flowers is their pollen. Using the NHMLA’s scanning electron microscope, or SEM, we can see the many tiny pollen grains that sit at the center of these flowers, waiting to be transferred to another poppy by an insect pollinator.
The diameter of poppy pollen in these species is just about 25 microns. To put that in context, 25 microns is less than the thickness of a piece of printer paper and nearly the diameter of a very thin human hair. Pollen are tiny! Touch the pollen-heavy anthers of a poppy and you’ll see it as orange dust on your fingers. Magnify that dust over 700 times and it looks like Tuscan melons (Caifornia poppy) or deflated “gripper” novelty footballs (Matilija poppy).
The often-textured surface of pollen is called the exine, and its pattern and other characteristics are helpful in identifying the plant species it comes from. In both of these poppy species, the exine is spinulose (with numerous tiny spines), and in Coulter's Matilija poppy the exine is also reticulate (like a net).
So, although we can’t bask in the beauty of millions of poppies blooming this year, maybe we can marvel at the millions of pollen grains produced by poppies all over Los Angeles, super bloom or not.