Monday, May 11, 2009
Polygala paucifolia - Fringed Polygala, Gaywings
Fringed Polygala is known from just one area in Indiana. One of the earliest reports came from Marcus W. Lyon of South Bend, who showed it to Charles Deam in the 1930’s. After the dreadfully hot drought of 1988 many northern plants that reach their southern limit here began to diminish and disappear. Polygala paucifolia dwindled to only a few plants, and it seemed apparent that the end was near. Fortunately, the plants have increased dramatically in recent years and flowered by the hundreds last year, marking an extraordinary comeback. On Saturday I went hill climbing and visited the two known colonies - one predominantly the white-flowered form, and one the typical pink color. They were at the peak of flowering and again flowering by the hundreds, with more plants present but not flowering. It was a spectacular show!
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Once again, great photos! I also enjoyed the observational information regarding the fluctuations in population numbers. I have been observing similar "bust and boom" years for several species on my property. Two years ago we had a dry year, following several dry years, and many of the corresponding dry-loving plants bloomed in profusion. The last two years have been quite wet and those same species are much less floral. Of course, other species are now more abundant. It is fascinating to watch the ebbs and flows of nature across so short a time span and to know that the ranges of species have been established by these and other processes. Such inherent resilence is the primary stance for the conservation movement, though rarely is it expressed as such.
One Saturday in 2006 I went on a mission to relocate Epigaea repens, Trailing Arbutus, at many of the places where I had found it decades earlier. I was pleasantly surprised to find it at most or all of the sites, though in almost all instances the colonies had decreased in size. But the amazing thing is that many of the colonies had migrated down slope!
In northern Indiana this plant grows on very steep slopes (facing north, east, or northeast, and the closer to vertical, the better) in sand country, and it has a definite affinity for mossy places without competition from any vascular plants. The moss probably traps and holds moisture, and I’ve often wondered if symbiosis of some type is going on. In addition, it very often grows about a third of the way down slope. At sites where Epigaea was growing among mosses, it was still present at the same place I remembered, but where mosses were not present, Epigaea had definitely migrated downwards. I believe it did so because of moisture requirements not being met during repeated droughts.
I have not, however, noticed a down slope trend in populations of Polygala paucifolia, even though it grows in the same kinds of places as Epigaea repens.
I'm sure you know Aldo Leopold's Sand County Almanac has some great "bust and boom" thoughts and observations, as well as Fred Case's orchid book.
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