Not really a flower

There is a time in early winter or late autumn when something unusual happens in the Missouri outdoors. Cooler nights cause most weedy plants to slow the movement of sap upward and they die. But some perennial plants maintain a living root system and sap in the lower stem lies waiting for the first frosty night.

When air temperatures fall below freezing the skin of the stem will contract and split a tiny bit, and sap will bleed slowly out where it will freeze causing thin, ribbonlike formations called frost flowers. Frost flowers are very dainty and melt quickly in sunlight or warming morning temperatures.

Early mornings after each of the first couple freezing nights in late autumn are the optimum time to hunt frost flowers. I believe the plants I found these frost flowers on were yellow ironweed.