The drive is intensifying to collect and screen more natural products for their medicinal effects. Says Gordon Cragg, chief of the National Cancer Institute's natural-products branch: "Nature produces chemicals that no chemist would ever dream of at the laboratory bench." All this is heartening for biologists and environmentalists concerned about the dwindling of the planet's biodiversity, mostly concentrated in a wide girdle around the equator. Human activity, from farming to logging and road building, is chewing at this girdle, driving countless species to extinction even before they have been discovered. "I see ethnobotany--the study of the relationship between people and plants--as the key to the preservation of this vast collection of species as well as a pathway to halting many diseases," says Cox.

Cox, 44, a Mormon, first came to Samoa in 1973, when he was assigned to the country for his two-year compulsory missionary service after he graduated from Brigham Young as a botany major. His father was a park ranger and his mother a wildlife and fisheries biologist; his grandfather created the Utah state park system; and his great-grandfather was a founder of Arbor Day. Cox naturally expected to end up involved in conservation, but his stint in Samoa surpassed all his expectations.

He was not only impressed by the far-reaching influence of botany that he witnessed--beginning with the scene of a Samoan fisherman using a plant to poison fish in a river--but he also learned to speak and write Samoan better than many Samoans. (A difficult language, Samoan in its most elegant form requires extensive knowledge of local ritual and legend.) Cox went on to earn a doctorate in biology at Harvard, then joined Brigham Young's faculty as a botanist studying plant physiology and pollination.