I retired in 2009 as director of the Arnold Arboretum and Arnold Professor. As an undergraduate I studied the diversity of North American birds, went to graduate school to become an ornithologist, and switched half way through to plants. Following my graduate degree, I taught plant ecology at Harvard for eight years and conducted research on the demography of wild populations of violets. After a stint as program director at the National Science Foundation, I became director of the botanic gardens and arboretum at Cornell University where I also taught plant ecology for six years. From there I returned to Harvard to direct the Arnold Arboretum for twenty-one years. My interest in birds and plants continues.