Abstract
Four varieties of G. fujikuroi are described on the basis of mating groups, variation in ascospore and perithecial size, phialide type and microconidial formation. The varietal type, G. fujikuroi var. fujikuroi, found only on rice, has the smallest ascospores and perithecia; microconidia are formed from phialides in false heads or chains. The largest ascospores, intermediate-size perithecia, presence of polyphialides, and microconidia only in false heads characterize G. fujikuroi var. subglutinans. Large ascospores and perithecia, phialides bearing microconidia in chains, and a diverse host range are features of G. fujikuroi var moniliformis stat. et comb. nov. [G. moniliformis]. A new mating group, G. fujikuroi var. intermedium var. nov., produces the largest perithecia, small ascospores, polyphialides and phialides, and microconidia in chains or false heads. Anamorphs are varieties of F. moniliforme.