Zygomycetes are usually fast growing fungi characterized by primitive coenocytic (mostly aseptate) hyphae. Asexual spores include chlamydoconidia, conidia and sporangiospores contained in sporangia borne on simple or branched sporangiophores. Sexual reproduction is isogamous producing a thick-walled sexual resting spore called a zygospore.
- Lichtheimia (Absidia)
Most isolates are heterothallic i.e. zygospores are absent, therefore identification is based primarily on sporangial morphology. This includes the arrangement and number of sporangiospores, shape, color, presence or absence of columellae and apophyses, as well as the arrangement of the sporangiophores and the presence or absence of rhizoids. Growth temperature studies (25,37,45C) can also be helpful. Tease mounts are best, use a drop of 95% alcohol as a wetting agent to reduce air bubbles. For specific identification see an appropriate text book.
Laboratory identification of some zygomycetous fungi, especially Apophysomyces elegans and Saksenaea vasiformis may be difficult or delayed because of the mould's failure to sporulate on the primary isolation media or on subsequent subculture onto potato dextrose agar. Sporulation may be stimulated by the use of nutrient deficient media, like cornmeal-glucose-sucrose-yeast extract agar, Czapek Dox agar, or by using the agar block method described by Ellis and Ajello (1982) and Ellis and Kaminski (1985).