ACKNOWLEDGMENTS

For numerous helpful suggestions, lists of common flowers, herbarium and fresh specimens for use in preparing illustrations, and for assistance in many other ways, the author and illustrator proffer sincere thanks to the following: Glen Bean, L. Floyd Keller, Walter B. McDougall, and William R. Supernaugh of the National Park Service; Dr. Norman C. Cooper, research associate, Allen Hancock Foundation; Mrs. Robert Gibbs, Isle Royale National Park, Mich.; Leslie M. Goodding, St. David, Arizona; Edmund C. Jaeger, Riverside Junior College, California; Thomas H. Kearney, California Academy of Sciences; Robert H. Peebles (who kindly reviewed the manuscript), director of the U. S. Field Service Station, Department of Agriculture, Sacaton, Arizona; Paul Ricker, president, Wildflower Preservation Society, Washington, D. C.; and Barton H. Warnock, head of biology department, Sul Ross State College, Alpine, Texas.