A monograph of Rhizopus

Zheng R. Y., Chen G. Q., Huang H. & Liu X. Y. (2007) A monograph of Rhizopus.

Sydowia 59 (2): 273–372.

A total of 312 Rhizopus strains comprising 187 strains isolated in China and 125 strains from foreign countries have been studied, which include possibly all of the cultures derived from types available now. The morphology of the sporangial and zygosporic states, maximum growth temperature, mating compatibility, and molecular systematics were used as important reference for the classification of the genus. Seventeen taxa, ten species and seven varieties, are recognized in the genus Rhizopus in this study. These include: R. americanus, R. arrhizus var. arrhizus, R. arrhizus var. delemar, R. arrhizus var. tonkinensis, R. caespitosus, R. homothallicus, R. microsporus var. microsporus, R. microsporus var. azygosporus, R. microsporus var. chinensis, R. microsporus var. oligosporus, R. microsporus var. rhizopodiformis, R. microsporus var. tuberosus, R. niveus, R. reflexus, R. schipperae, R. sexualis, and R. stolonifer. Seventy-two names of Rhizopus are treated as synonyms. Twenty-five species, eight varieties and one form are thought to be doubtful, and nine species and four varieties are excluded from the genus. Neotypes are designated for R. microsporus var. microsporus, R. microsporus var. oligosporus, R. microsporus var. rhizopodiformis, and R. stolonifer. In the taxa accepted, zygospores are found and studied in all the three homothallic species and five heterothallic species or varieties; while azygospores are found in two species and one variety. A synoptic key and a diagnostic key, as well as synonyms, descriptions, and line drawings are provided for all taxa recognized.

Key words: Mucorales, Zygomycota, taxonomy, morphology, holomorph.