Frost Flowers

While hiking at Bell Smith Springs in Southern Illinois an early cool fall morning we came along these "ice flowers" along the trail. This is what I found out about them at WIKIPEDIA.com.

Frost flowers is the name commonly given to a condition in which thin layers of ice are extruded from long-stemmed plants in autunm or early winter. The thin layers of ice are often formed into exquisite patterns that curl into "petals" that resemble flowers.
The formation of frost flowers, also known as "ice flowers," is apparently dependent on a freezing weather condition occurring when the ground is not already frozen. The sap in the stem of the plants will expand (water expands when frozen), causing long, thin cracks to form along the length of the stem. Water is then drawn through these cracks via capillary action and freezes upon contact with the air. As more water is drawn through the cracks it pushes the thin ice layers further from the stem, causing a thin "petal" to form. In the case of woody plants and tree branches the freezing water is squeezed through the pores of the plant forming long thin strings of ice.
Frost flower have a brief life span so early morning is the best time to find them. The first rays of sun will begin the melt down. On the average frost flowers begin forming with the first hard freeze continuing through early December.