W.W. Eggleston collection of William C. Cusick

William Conklin Cusick was born February 26, 1842 in Adams County, Illinois. He was educated in country schools in Illinois until age 11 when his family migrated west along the Oregon trail. The eldest of five children, William walked most of the way, driving an ox-team, and settled with his family in the Willamette Valley. He continued his education in rural schools until age 20, when he entered La Creole Academy in Dallas, Polk County for one and half years. After a two year stint of teaching, he returned to the Academy, leaving in 1864 to enroll at Willamette University in Salem. There he studied higher algebra, physics and geology until enlisting in the Union Army in 1865.

During his year of army service in Idaho and Eastern Oregon, Cusick developed an interest in botany. He began his first collection of plant specimens, and the first of five phases of plant collecting. Cusick returned to teaching until 1872, when he moved to Eastern Oregon with his brother, S. Frank Cusick, settling on Cusick Creek in Union County. He published plant lists, and began selling his seeds, plants, and mounted specimens to nurseries and botanical gardens. He spent the winter of 1910 at the University of Oregon Herbarium in Eugene, until poor health forced his early return to Union County.

Cusick's failing eyesight and consequent eye operations for cataracts between 1913-1916, limited his collecting activity. In 1914, Professor C.V. Piper requested his associate agronomist at the Bureau of Plant Industry, Willard W. Eggleston, to begin corresponding with Cusick in hopes of working on a flore of the Blue Mountains. Eggleston spent a week botanizing with Cusick and made plans to return to continue the work, although it was interrupted by World War I.

Cusick's plant collection numbered nearly 5,000. He discovered dozens of new species, nearly forty of which were named after him. His specimens collected up to 1912 are preserved in the Cusick Herbarium at the Univeristy of Oregon which he sold to them in 1913. Washingon State University acquired his later herbarium. Cusick died at his brother's home in Union, Oregon on October 7, 1922. In 1924, Eggleston compiled a biography of Cusick, several drafts of which are included in this collection.