Describes plant tissues that naturally contain substances poisonous to human beings if taken in large amounts. Some of these toxic materials are found in vegetables and fruits, as well as plants we normally don't eat such as yew. Also notes that plants recently sprayed with pesticides are harmful. (BR)

Discusses U.S. National Parks as natural laboratories for the study of ecology, geology, earth science, and botany. Suggests activities which will enable children to more fully appreciate the great age of the earth, its history, the complexity of its structure and composition, and the myriad plants and animals which inhabit it. (BR)