Cornelius Lott Shear (March 26, 1865 February 2, 1956) was an American mycologist and plant pathologist who served as a senior pathologist at the USDA Bureau of Plant Industry.

[1] Born in Coeyman's Hollow, Albany County, New York, on March 26, 1865, Shear was the first to describe the grass Bromus arizonicus.

[2] He was a pioneer in the study of pathogenic fungi who studied crop diseases and developed control measures for treatment of economically-important crops such as cranberries, grapes and cotton.

[1][3] Shear edited the exsiccata series New York fungi.

[4][5] He played a pivotal role in creating the American Phytopathological Society, founded in 1908.