He was born May 30, 1909, to Roy and Elizabeth Cooper Skinner McVaugh. He grew up in Kinderhook, N.Y., and went to George School and Swarthmore College, where he graduated in 1931. He completed a Ph.D. in botany at the University of Pennsylvania in 1935, taught briefly at the University of Georgia and then worked for the Department of Agriculture during the Second World War.

He came to the University of Michigan in 1946 and retired in 1979 as Harley Harris Bartlett Professor of Botany; the following year he moved to Chapel Hill, where he became Research Professor of Botany at UNC, a position which he held until his death.

Much of his career was devoted to the study of the flora of a botanically rich region of western Mexico, based on extensive field work over many years, which resulted in the discovery of a large number of new species of plants; the volumes describing this flora brought him scientific honors and international recognition. The establishment of a large nature reserve named for him, in the region which he had studied so intensively, was announced at his birthday celebration in June.

His wife, Ruth Beall McVaugh, died in 1987. He is survived by a son, Michael, of Chapel Hill; a daughter, Jenifer, of Golden Lake, Ontario; two grandsons; and three great-grandchildren.

Memorial contributions may be made to the UNC Herbarium Building Fund at the N.C. Botanical Garden, Campus Box #3375, UNC-Chapel Hill, Chapel Hill, NC 27599-3375