Skunk cabbage, found in the northern 2/3's of the state in open swamps, marshes, and wet woodlands, is Illinois' earliest flowering plant. Before the woods awake in spring, it begins to bloom in late February or early March. Sheltered and hidden by a few decaying leaves, skunk cabbage bravely pokes through the moist earth to face howling winds, freezing temperatures, and sometimes even snow.
The first part of the plant to appear is not the leaves, but a fleshy protective hood, called a spathe. The hood, emerging dark and ruddy from the mud, is brownish-purple with yellow and green streaks and spots. Although the hood may be 3 to 6 inches tall, its color blends with the surrounding decaying leaves on the forest floor. Using energy stored for months in starchy, tuberous roots, the plant generates enough heat not only to melt through leftover snow, but to maintain summer-like temperatures inside the hood on subfreezing mornings. This is important as each hood incubates a knob-like structure, called a spadix, which is covered with tiny, cold-sensitive blossoms. The insulating walls and curved design of the hood allow eddies of warmed air to circulate around the developing flowers.
All parts of the plant, when bruised or crushed, give off an offensive odor that has been described as a cross between garlic, onions, and decaying flesh. The heat produced by the plant as it grows helps to volatilize the odor, which in turn, attracts carrion flies that are necessary for cross pollination.
A few days after the hood emerges, the leaves pierce the mud. Still unsure of the weather, they remain rolled into compact cones and cower behind the protective hood. As spring advances the odor subsides, the flowers shrivel, and the leaves begin to grow and spread. By summer the skunk cabbage is no longer the ground hugging spathe, but knee-high clumps of caladium-like leaves.