War on the Prairie!

From a distance, a prairie often appears to be a scene of harmony. Indeed, it is, with numerous stable relationships formed over millennia among plants, microbes, insects, and other animals. However, beneath this harmonious facade lies a challenging world of negotiation, conflicts, and alliances, where some participants gain advantages while others face disadvantages- a kind of war going on! One of the "weapons of war" on the prairies is allelopathy, a process whereby a plant releases a chemical that hinders the growth of surrounding plants.

Some pussytoe species are examples of an allelopathic plant. Named for their spring flowers that resemble tiny cat feet, these plants are commonly found on our bluff prairies. They are dioecious, meaning there are distinct male and female plants. This trait helps prevent inbreeding by necessitating cross-pollination, but it also relies on locating a nearby partner. The male plants feature stamens that resemble insect antennae, which is why the genus is named Antennaria.

Here is a fairly uniform patch of pussytoes growing on Zoerb Prairie on October 5 without much else invading its space:

The underside of the leaf shown has 3 veins and there are some hairs on the tops of the leaves. These features, as well as the leaf shape suggest that this is likely to be plantain-leaved pussytoes, or Antennaria plantaginifolia, as shown in the photo below:

This species is known to be one of the pussytoes that is allelopathic. It is also known to be a host plant for the American Lady butterfly. Interestingly, it is also called "women's-tobacco" because, back in the day, it was felt to be a "milder" version of conventional tobacco deemed more suitable for women. Oh brother!

Next we see a Great Plains Lady's Tresses orchid, or Spiranthes magnicamporum, growing just at the edge of one of these patches. It appears withered and overall not very healthy:

Compare it to this one growing on another part of the prairie:

Notice the difference? Many factors might be responsible for this variation- as mentioned in an earlier post about this plant, https://www.friendsoftheblufflands.org/post/the-ladies-have-it , this plant is rather finicky. However, it could also be a case of allelopathy at work!

Allelopathy is just one of the many interactions that help maintain the balance and beauty of the prairie. So, the next time you're admiring the stunning beauty of the prairie and its perfect mosaic of plants covering the hillside, remember that beneath it all, a war is taking place!