associated with and led Sierra Club outings for several weeks at a time, after which he published "Base Camp Reports." Published from 1950 to 1956, these reports covered a wide range of subjects, including plant lists, insects, and ecology. His first such report, at the age of 14, summarized 506 plant collections representing 337 species collected in the Sierra Nevada Mountains in Inyo and Fresno Counties. G. Ledyard Stebbins was a counselor on this particular trip, identified by Raven as Prof. G. L. "Led" Stebbins. During this time he also published on new weed species and other plants found in and around San Francisco as well as the Sierra Nevada Mountains. In 1950 Raven, at the age of 14, had collected a plant called C. rubicunda. In the early 1950s, in the course of revising the genus Clarkia Harlan Lewis and his wife Margaret Lewis discovered the herbarium specimen collected by Raven. They visited him in 1952 when he was 16, and wanted to know where the collection was made. Lewis eventually located the new species, and in 1958 Lewis and Raven published a botanical description of this plant, called C. franciscana, which was morphologically very closely related to C. rubicunda and C. amoena. Evolution While a graduate student at the University of California, Los Angeles, Raven and Harlan Lewis published a major paper in 1958 on the evolution of C. franciscana, and generalized to what was by then a general a pattern of speciation in Clarkia. They concluded that C. franciscana had evolved from Clarkia rubicunda; and they asserted that C. franciscana's origin mirrored a recurring theme in Clarkia of a derived species showing a close morphological similarity to a parental species, the derived species being geographically proximal, but differing from the parent by chromosomal differences and showing interspecific sterility. Further, they hypothesized that such speciation in Clarkia was rapid, and perhaps occurred within the last 12,000 years. Additionally, they hypothesized that this rapid mode of speciation seen in Clarkia was analogous to a mode of speciation known as quantum evolution. Following his early publication in 1958 on evolution of C. franciscana, Raven went on to publish many papers on evolutionary topics. While at Stanford University, with Paul R. Ehrlich, he coined the term coevolution after a 1964 review of butterflies and their food plants. In a 1969 paper Ehrlich and Raven were also critical of the idea that