Friday, June 27, 2014

Great Balls of Flower! Buttonbush and Sensitive Briar

In March and April, we reveled in the diverse wildflowers of the forest floor, gleaning just enough sunlight from the open canopy; but in June, when the leaves are thick and green and the forest floor is dark and barren, the action has moved to the margins, the roadsides and ditches and open meadows...

And, if we're vigilant, when we're out and about, scurrying from one client to the next, we may catch a glimpse of these sun-loving bloomers, basking in the life-giving light. 
 This stunning beauty, littleleaf sensitive briar, Mimosa microphylla, was hanging out on the corner with greenbrier and maple, and we happened upon it in full bloom.  

The spectacular spherical blossoms have an exotic, tropical look, but sensitive vine is a native Southerner in the pea family, Fabaceae, although it doesn't have the classic blossom structure associated with many of the legumes.

Sensitive briar or sensitive vine takes its name from the tendency of its leaves to fold up or close when touched or stimulated. This is a fascinating process known as thigmonasty, and is achieved when the plant reduces the turgor pressure in a given leaflet, causing it to droop at the joint and "close" the leaf.

Ecologists believe this may be a defense mechanism; when an herbivore begins to munch on the tender leaves, the leaflets close up and appear to vanish, and the would-be diner is exposed much more readily to the prickly stem beneath as well.

As luck would have it, we spotted another early summer bloomer with similar globe-shaped blossoms just around the corner.

Although this individual was nearing the end of its blooming, we still managed to locate a few fresh blossoms amidst the profusion of older ones. This is the buttonbush, Cephalanthus occidentalis, and it is a wonderful native shrub. 

Besides its obvious aesthetic appeal, with abundant showy flowers and lush green leaves, bees make honey from the nectar, and the seeds are eaten by a number of different species of waterfowl and shorebirds. Whitetail deer love the twigs and leaves, and it provides habitat and shelter for a number of other animals. 

We were pleasantly surprised to find this bush in a roadside ditch, far from any obvious water source, because buttonbush loves the water. 

It is most often found in open marshes or along the sunny margins of ponds and streams, and can actually grow and thrive in up to three feet of water.

The ditch here adjoins a clump of low rich woods, so perhaps the site is wetter than it appears, particularly since the bush has flowered so abundantly. 

As the summer progresses, the seeds will mature inside the button balls and linger on the plant into fall. 

In the meantime, we'll keep our eyes open for more roadside summer surprises and share them when we can.

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