In December, Thoreau used to go hunting for hopeful signs of spring. A bit early, you say? Not when the quest was for skunk cabbage.Just as winter is beginning, this wildflower is sending up its odd-looking and foul-smelling buds through ground that may already be frozen. It can do this because the club-like spadix, which bears its flowers, has the ability to produce heat, a process called \u201cthermogenesis.\u201d The spadix is protected by a cloaklike spathe, which keeps out the cold air and keeps in the warmth. Even when the outside temperature is freezing, the spadix can heat itself to 70 degrees.In early March when snow is still on the ground and spring is still weeks away, skunk cabbage is already ready to bloom, and its hot pocket will welcome bees, flies and other early insects to a tiny, almost tropical microclimate\u2014J.S.