Job Bicknell Ellis (January 21, 1829 – December 30, 1905) was a pioneering North American mycologist known for his study of ascomycetes, especially the grouping of fungi called the Pyrenomycetes (known today as the Sordariomycetes).

He collected specimens extensively, and together with his wife, prepared 200,000 sets of dried fungal samples that were sent out to subscribers in series between 1878 and 1894.

He saw a copy of Henry William Ravenel's Fungi Caroliniani Exsiccati, a set of dried specimens (exsiccata) collected and distributed from North Carolina and area.

[1] Ellis taught in a public school in Potsdam village in 1863,[2] and later served on the Union side in the American Civil War from 1864 to 1865.

The war took its toll on his spirits; his April 22, 1865, diary entry reads: "I have felt degraded ever since I have been here & no amount of money & I might perhaps safely say no motive not even patriotism will ever induce me to put myself in the like position again.

Although he did not have any formal training as a botanist or mycologist, Ellis gradually took up mycological fieldwork and ultimately dedicated his life to the collection and exchange of dried fungal specimens.

Based in Newfield, New Jersey, Ellis maintained an extensive correspondence with many renowned American and European mycologists.

In 1880, Ellis began to receive financial support from Benjamin Matlock Everhart, a wealthy merchant of West Chester, Pennsylvania.

He published many of his newly discovered species in the journal, as well as the Botanical Gazette, Torrey Bulletin, American Naturalist, and Proceedings of the Philadelphia Academy.