This time of year, the late-summer wildflowers you savored in August and September are seeding out. Some become almost unrecognizable this time of year, having turned the autumnal tones of yellow and brown and replacing showy flower heads with seed pods of all shapes and sizes.
You're probably familiar with common milkweed (Asclepias syriaca): a monarch butterfly favorite. Each fall, milkweed's seed pods dry and crack open, distributing small brown seeds on silky filaments, blown around in fall winds. Butterfly weed (Asclepias tuberosa), a species of milkweed, is no different. Take a look at butterfly weed this summer in all its orange glory (below and upper left), and how it looks now with seed pods prepped to pop (upper left corner).
Wild sensitive plant, a member of the pea family, (Chamaecrista nictitans) is another wildflower you can now see plainly in seed form. Instead of bulky pods full of silky fibered-seeds, wild sensitive plant has slender, flat pods lined with black seeds. In the summer, these seed pods are green and look a lot like snow pea pods. As you can see from the photos below, this flower's fall appearance is a far cry from its bright yellow, floppy-flowered summer look.
Photos below, from top: butterfly weed in summer; wild sensitive plant in bloom; and two shots of wild sensitive plant in October.