25 September 1987
Vol 237, Issue 4822

About The Cover

The thermogenic inflorescence of Sauromatum guttatum Schott, voodoo lily (right) and its thermographic image (left) on the day of flowering. Each 1°C difference in surface temperature corresponds to a different color. The appendix, upper cylindrical part of the inflorescence, is about 9°C warmer than the rest of the plant. This heating is triggered by salicylic acid which moves into the appendix 1 day before inflorescence unfolding. The heat is used to volatilize putrid-smelling compounds attractive to insect pollinators. See page 1601. [M. E. Nuttall, Photo Services, Du Pont Experimental Station, Wilmington, DE 19898]