Taxonomy and identification of mucormycosis-causing fungi I. Synonymity of Absidia ramosa with A. corymbifera

The validity of the species Absidia ramosa (sporangiospores regularly elliptical to ovoid) or its synonymity with A. corymbifera (sporangiospores spherical to irregularly ovoid) was studied in 56 pertinent strains including the 2 neotype strains described by Ellis & Hesseltine (1966). For each strain, the length and breadth of 200 unselected sporangiospores were measured microphotographically and the length expressed in mean percentage of the breadth. The minimum mean was 104·9% for the most spherical-spored strain and the maximum 167·1% for the most eliptical-spored one, but the means of the remaining 54 strains were continuously distributed between the two extremes redering any demarcation impossible or arbitrary. Independently of the mean form, morphological variation and mean size of the sporangiospores were randomly distributed among the strains. The 56 strains were crossed with each other (1540 crossings). Zygospores were produced with all strains, but there were marked differences in mating capacit...