to disperse its scent—that of rotting meat—above the cold air that settles over it at night in its natural habitat. Contrary to popular belief, the western skunk cabbage (Lysichiton americanus), a close relative from the family Araceae, is not thermogenic. Outside Araceae, the sacred lotus (Nelumbo nucifera) is thermogenic and endothermic, able to regulate its flower temperature to a certain range, an ability shared by at least one species in the non-photosynthetic parasitic genus Rhizanthes, Rhizanthes lowii. Heat production Many endothermy plant species rely on alternative oxidase (AOX), which is an enzyme in the mitochondria organelle and is a part of the electron transport chain. The reduction of mitochondrial redox potential by alternative oxidase increases unproductive respiration. This metabolic process creates an excess of heat which warms thermogenic tissue or organs. Plants containing this alternative oxidase are unaffected by the effects of cyanide because AOX acts as electron acceptor collecting electrons from ubiquinol while bypassing the third electron complex. The AOX enzyme then reduces oxygen molecules to water without the presence of a proton gradient which in turn is very inefficient yielding a drop in free energy from Ubiquinol to oxygen which is released in heat. References Heat transfer Plant physiology Plants by adaptation