After about an hour of wandering and photographing, I found this...
|A fall -blooming Marsh Marigold|
That's a Marsh Marigold (Caltha palustris) that has recently finished flowering! The pistils and stamen are still visible, but the petals have dropped off.
Nearby I saw another one.
|A Marsh Marigold bloom in December!|
This plant had complete flowers (including petals).
Why am I so surprised to find a flower in bloom?
I'm not surprised to find a flower. I almost expected to find a few late fall wildflowers hanging on in a secluded area of the swamp. Some of these flowers will continue until they are covered with snow or until an extended period of cold weather kills them off. A few minutes earlier I had found a single goldenrod plant in bloom. This is the kind of flower that didn't surprise me.
I am, however, very surprised to find a Marsh Marigold in bloom. It's the 7th of December. December! The Marsh Marigold is a spring wildflower. In Mid-Michigan, it normally flowers between April and June. When I did my Wildflower Big Year in 2014, I found my first Marsh Marigold bloom on April 29th.
So what is happening here?
I expect that that relatively warm fall and lack of snow has this flower confused. The air and soil temperature fooled the plant into thinking it was spring and the plant responded by sending up leaves and then flower buds. Many spring wildflowers will send up shoots in the fall, but they are killed back by frost or snow - this plant just managed to flower before the cold killed it off.
|A small spot of yellow in an otherwise dull December swamp|