Gone but not forgotten…Thismia Centennial Hunt at Indian Ridge Marsh!

Ever wanted your name to go down in conservation history? Well, now may be your chance. On Sunday, August 21, 2016, the Thismia Centennial Hunt will take place at Indian Ridge Marsh in Chicago’s South Side Calumet region. The hope is to rediscover Thismia americana, a unique plant species last seen in Chicago in 1916 and thought to be extinct. The site of the hunt includes the area at Indian Ridge Marsh where the Wetlands Initiative recently began hemi-marsh restoration in partnership with Audubon Great Lakes. TWI ecologist Trevor Edmonson is part of that restoration and is also one of the organizers of the hunt.

Thismia americana is the only flower endemic to Chicago. In August of 1912, graduate student Norma Pfeiffer was traversing an area of wet prairie on the city’s South Side when she spotted a strange flower peeking out of the soil. The description of this tiny flower would subsequently lead to her Ph.D.

Illustration by Miriam W. Meyer from Mohlenbrock, R.H. 1970. The Illustrated Flora of Illinois. Copyright 2015 by Southern Illinois University Press.

The plant she had stumbled upon was Thismia americana, a species that had confounded botanists across North America. It is a member of the Burmanniaceae family, which means it is a mycoheterotroph. Mycoheterotrophs survive by parasitizing mycorrhizal fungi found in the soil. Instead of having leaves and using chlorophyll to photosynthesize, it uses stored-up energy from rotting plant matter to produce a very small, translucent, white and blue-green striped flower that barely reaches above the soil surface. Its tiny, low-lying flower makes this plant very difficult to see.

Another reason T. americana is so unique is that the family to which it belongs has a tropical distribution, very unlike Chicago’s climate. Its closest relatives have been found growing in Australia and New Zealand.

Pfieffer continued to study T. americana for five years after her initial discovery, but 1916 was the last time anyone saw the plant. Since then, much of the land in the Calumet region was converted for industrial purposes and the habitat where T. americana was once found has largely disappeared. But many people still have hope that the plant could be hiding somewhere at Indian Ridge Marsh.

Map of survey points for monitoring Indian Ridge Marsh plant communities. Created by TWI GIS Analyst Jim Monchak and Senior Ecologist Gary Sullivan.

Even though previous hunts have not turned up any T. americana, other rare plant species for the region have been recorded, which makes the hunts worthwhile and exciting. Recently, as part of the restoration at Indian Ridge Marsh, TWI's senior ecologist Dr. Gary Sullivan and GIS analyst Jim Monchak created more than 50 survey points for monitoring plant communities in the coming years there. Pre-restoration surveys found relatively few native species, but they did find some unexpected plants like hop sedge. Since many hunters will be carefully combing the area in search of thismia on August 20, they may come up with a few more species to add to TWI’s survey list.

But will they come up with Thismia americana? Opinions on whether or not this mysterious plant will ever be found again vary greatly. “Let’s just say I wouldn’t bet a large amount of money on it,” says Dr. Sullivan. Others remain more hopeful and believe that since T. americana is such a minuscule plant, maybe it’s been blooming covertly all these years, with no one to see. Trevor Edmonson disagrees with his boss, saying, “Is thismia still out there? I think so. I hear stories from past hunts where they hid small beads in an effort to train the eyes of volunteers. Not many beads were found. I also believe we don't know enough about the ecology of thismia. Many plants disappear for several years and when the time is right show up again. No one has been there at that right time just yet for thismia.”

If you’re unsure whether thismia still exists, come join in the hunt. August is the perfect time to search for Thismia americana because it has only ever been recorded between July and mid-September during the time when it flowers and fruits. For the rest of the year, it remains underground and out of sight. Whether or not T. americana is found on August 20, the hunt is a great opportunity to see Indian Ridge Marsh and get a look at the restoration starting there. For your chance at common naming rights for this incredibly distinct species, check out the Thismia Centennial Hunt!