One of his teachers was botanist Charles Bessey, who inspired Clements to research topics such as microscopy, plant physiology, and laboratory experimentation.
[1] While employed at Carnegie Institution of Washington, Clements faced criticism for his experiments conducted with the purpose of creating new plant species.
Due to these criticisms and as well as personal conflicts with his co workers, in the 1920s the title of director of research in experimental taxonomy was given to Harvey Monroe Hall.
In these studies, he and Roscoe Pound (who subsequently moved from ecology to legal scholarship) developed the widely-used method of sampling using quadrats around 1898.
[8][9][10] Clements's climax theory of vegetation dominated plant ecology during the first decades of the twentieth century, though it was criticized significantly by ecologists William Skinner Cooper, Henry Gleason and Arthur Tansley early on, and by Robert Whittaker mid-century, and largely fell out of favor.
Ecologist Arthur Tansley wrote that because of his support for Lamarckism, Clements "never seemed to give proper weight to the results of modern genetical research.
"[15] Science historian Ronald C. Tobey has commented that: [Clements] believed that plants and animals could acquire a wide variety and range of characteristics in their struggle to survive and adapt to their environment, and that these features were heritable.