De Vries (d? vr?s?), Hugo 1848-1935. Dutch botanist who championed Gregor Mendel’s works and emphasized mutation rather than natural selection as the primary mechanism of evolution.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.