In the fall and winter, we generally spend more time powered down to rest and recharge. Nature is generally very similar as animals hibernate, trees lose their leaves and a blanket of snow covers us all.
There are exceptions but few in our area that reside in the plant world. One such plant is the putty-root orchid (aplectrum hyemale). During the fall and winter, this plant sends out a single green basal leaf that rises just above the leaf litter.
The orchid resides in wooded areas, and in the wintertime as the leaves fall, the canopy opens up allowing extra sunlight to reach the ground. The plant will photosynthesize off and on when uncovered by snow until spring when it sends up a small unassuming green flower stalk. During the late spring, the leaf withers away until it is yet time again to send up another in the fall. In northern Illinois, this plant is very rare, but it can be common in southern Illinois.
Another orchid in the state is the cranefly orchid (tipularia discolor). This plant also has a green leaf in the winter but it lacks the distinctive white veins of the putty root, which you can see in my picture here. When I am out hiking, I always take a second look at any green leaves I come across just to be sure.