CHAMPAIGN — John Ralph Alexander, 84, of Mahomet and Champaign died Sunday, Oct. 27, 2019, at Carle Foundation Hospital, Urbana.

Ralph Alexander was born Jan. 2, 1935, in Anniston, Ala. He married Stephanie Taylor on June 19, 1965.

He is survived by his wife, Stephanie; his sister, Martha Jane Alexander; as well as his in-laws, Gillian and Carman Bradley; his nieces, Mary Bradley, Lucy Bradley and Amy (Colin) Madsen; and his great-niece, Samantha Madsen.

Ralph earned his undergraduate degree in mechanical engineering and Ph.D. in mathematics at Purdue University. He was emeritus professor of mathematics at the University of Illinois at Urbana-Champaign and published groundbreaking research papers in geometry.

After retirement, he became interested in nature photography, and did many studies of tree branch and leaf patterns, and of the wildlife along the banks of the Sangamon River.

A memorial celebration will be held in the spring. The date will be announced later. Memorials may be made to the Land Conservation Foundation, 3413 Waterville Court, Champaign, IL 61822.