HEAT-PRODUCING FLOWERS

The flowers of some plants produce enough heat to raise their temperat ures as much as 35 degrees C above air temperature. Three species have been shown to regulate flower temperature within a narrow range by an unknown physiological mechanism that increases the rate of heat produ ction as air temperature decreases. Thermogenic plants occur only in a ncient families of seed plants, and have apparently evolved in associa tion with beetle pollinators. Because many beetles require high body t emperatures for activity, the warm environment inside thermo regulatin g flowers may be an energetic reward during their visits.