G. Ledyard Stebbins
George Ledyard Stebbins, Jr. (January 6, 1906 – January 19, 2000) was an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

 and geneticist
A geneticist is a biologist who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a researcher or lecturer. Some geneticists perform experiments and analyze data to interpret the inheritance of skills. A geneticist is also a Consultant or...

 who is widely regarded as one of the leading evolutionary biologists of the 20th century. Stebbins received his Ph.D. in botany from Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

 in 1931. He went on to the University of California, Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

, where his work with E. B. Babcock
E. B. Babcock
Ernest Brown Babcock was an United States plant geneticist. His pioneering work on the genetics of the genus Crepis and his more than 100 published articles explaining plant evolution primarily in terms of genetics mark him as a pioneer in the application of genetics research.- References :*...

 on the genetic evolution of plant species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, and his association with a group of evolutionary biologists known as the Bay Area Biosystematists
Bay Area Biosystematists
The Bay Area Biosystematists is a group of biologists, geneticists, paleontologists, and systematists that are also interested in evolution. The group has been active in the San Francisco Bay Area since 1936, and is notable as a connection between many of the leading evolutionary biologists of the...

, led him to develop a comprehensive synthesis of plant evolution incorporating genetics.

His most important publication was Variation and Evolution in Plants
Variation and Evolution in Plants
Variation and Evolution in Plants is a book written by G. Ledyard Stebbins, published in 1950. It is one of the key publications embodying the modern evolutionary synthesis, as the first comprehensive publication to discuss the relationship between genetics and natural selection in plants. The book...

, which combined genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 and Darwin's
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

 theory of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 to describe plant speciation
Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...