March Master Gardener Column

By Jan Phipps

March 2020


            March is a good month to catch up on horticultural research. Here are two topics you might find interesting. The first is how angiosperms eclipsed their competitors.

Four hundred million years ago ferns and conifers (cone-bearing plants) dominated the world. Flowering plants, also known as angiosperms, didn’t show up until two hundred million years ago, but when they did, they overtook the ferns and conifers. Two researchers, Adam Roddy of Yale University and Kevin Simonin of San Francisco State University set out to discover why.

           The answer is “genome downsizing” which is unique to flowering plants. The genetic instructions that create a variety of cells making up individual organisms are called a genome. It is still unknown how, but angiosperms somehow shrunk the size of their genome. Smaller genomes meant smaller, more efficient cells that could multiply faster and produce more nutrients, giving them an advantage over ferns and conifers. With their accelerated growth rate, angiosperms became the most plentiful and diverse group in the plant kingdom.

           So, why do ferns and conifers continue to survive when outnumbered by the more adaptable angiosperms? Roddy thinks it is because they find environmental niches that are less competitive. Ferns thrive on the densely shaded forest floor and other places where resources are scarce. Most flowering plants flourish in areas with more abundant resources.

           Hopefully, further research will determine why ferns and conifers haven’t utilized genome downsizing to become more competitive.

           The second research debunks the previous idea that houseplants clean the air in our homes. It was thought plants cleaned volatile organic compounds (VOCs) from the air but it turns out microbes are the cleaners, not the actual plant.

           It is still true houseplants give off oxygen but in such small amounts, it is negligible. You would need 10 plants for every square foot to notice a difference. The real hero is modern ventilation systems in our buildings and homes. It is responsible for continually bringing in fresh air from outside, and also filtering out VOCs.

           Still, plants in the home or workplace have psychological benefits that brighten our lives.

           The Edgar County Master Gardeners from University of Illinois Extension hope you enjoy our column and learn something new each month.  Contact us at 217-465-8585 with your gardening questions or visit