The word Mycology is derived from the Greek words Mykes meaning fungus and logos meaning knowledge. The branch of biology which deals with the origin, habitat, taxonomy, physical structure, reproduction, commercial production etc. of fungi is called Mycology. A person who specializes in fungi is called a mycologist. Scientist P. Micheli is called the father of mycology or mycology. Scientist D. Bari is called the father of modern mycology. C. J Alexopoulos is called the Linnaeus of mycology because of his early knowledge of fungi. According to Alexopoulos, chlorophyll-free, nucleated, avascular, mycelial structures whose walls are composed of chitin and cellulose and which reproduce asexually and sexually are called fungi.