Photo of the Week – June 23, 2017

This is a good year for sensitive briar (Mimosa quadrivalvus) in the Platte River Prairies.  Sensitive briar is a spiny perennial legume that sprawls across the ground in dry prairies and has leaves that fold up when touched or blown about by the wind.  It’s an odd plant, and one that is hard to miss when it’s blooming because each plant has numerous pink flower balls scattered across an area about the size of a large bathtub.

A sensitive briar plant blooming on a sandy hill this year in the Platte River Prairies.

Sensitive briar is named for the sensitivity of its leaves to touch, but it must also be sensitive to moisture conditions or something else.  As I was preparing to write this, I scanned through my field notes because I remembered sensitive briar being extra abundant a few years ago as well.  I was right; I’d noted an extraordinary number of plants back in 2011.  In fact, I wrote a blog post about it!  I don’t have any better explanation this year than I did back in 2011 for why this perennial plant seems to ebb and flow so much in abundance.

This katydid nymph was one of many insects enjoying the abundance (and easily accessible pollen) of sensitive briar this year.

Maybe the ebb and flow is mainly about flowering, and many of our sensitive briar plants just don’t bloom every year.  The only thing giving me pause is an experience we once had with a large plot of sensitive briar plants in our seed production garden.  One year, we thought all the plants had died because they didn’t even come out of the ground that spring.  We wondered if they’d been accidentally sprayed or something the previous year.  Fortunately, we didn’t till the plot up and start over because the next year it was filled with mature sensitive briar plants again!  It’s not that I’m looking for more data collection projects to work on, but it would sure be interesting to mark some plants in our prairies and track them over 10 years or so to see what’s going on…

Just one more fun prairie mystery to solve!

This entry was posted in Prairie Natural History, Prairie Photography, Prairie Plants and tagged , , , by Chris Helzer. Bookmark the permalink.

About Chris Helzer

Chris Helzer is the Director of Science for The Nature Conservancy in Nebraska. His main role is to evaluate and capture lessons from the Conservancy’s land management and restoration work and then share those lessons with other landowners – both private and public. In addition, Chris works to raise awareness about the importance of prairies and their conservation through his writing, photography, and presentations to various groups. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press. He lives in Aurora, Nebraska with his wife Kim and their children.

5 thoughts on “Photo of the Week – June 23, 2017

  1. I’d note that related Desmanthus illinoensis/i> (Illinois bundleflower) also folds when touched, but it takes rather longer (a minute or so), and the folding is not as complete, so it tends to go unnoticed.

  2. In my Texas neighborhood, we have both Mimosa quadrivalvus (sensitive briar) and Mimosa strigillosa (powderpuff). The basic difference seems to be that the sensitive briar has recurved spines along the stem, while the powderpuff has slight bristles.

    Both species are going absolutely wild this year. I’ve never seen so many. There are places where the powderpuffs are thick as dandelions, and out on some prairies, those darned thorny sensitive briars are everywhere. Up in the hill country, Mimosa borealis is doing well, too.

    It’s interesting that an exceptional bloom is spread out over such a large area.

  3. I’ll wager you have plenty of Blue butterflies around since sensitive briar is an excellent host plant for their caterpillars.

  4. Chris, this story brings back memories. When our kids were small we’d plant Mimosa seeds in a pot and once the plats emerged the kids were fascinated that they could touch the leaves and watch them fold up. Good memories!

    Sent from my iPhone



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