OBSERVATIONS ON THAMNIDIACEAE (MUCORALES) .6. 2 NEW SPECIES OF DICHOTOMOCLADIUM AND THE ZYGOSPORES OF D-HESSELTINEI (CHAETOCLADIACEAE)

Two new species are described in Dichotomocladium. One species with globose sporangiola, D. sphaerosporum, was isolated from dung collected in Mianwali, Pakistan, and is similar to D. elegans in its general habit. The second species with obovoid sporangiola, D. floridanum, was isolated from dung collected in Gainesville, Florida, and resembles D. robustum. The zygospores of D. hesseltinei have hemispherical suspensors and are described for the first time. Chaetocladiaceae is revived for fungi having branched (dichotomous, verticillate) fertile hyphae, pedicellate, unispored sporangiola which are produced on fertile vesicles, and sterile spines. Dichotomocladium is transferred to Chaetocladiaceae, which contains only one other genus, Chaetocladium. Chaetocladium and Dichotomocladium each are considered monophyletic, and together comprise the monophyletic Chaetocladiaceae. Keys are provided to the genera of Chaetocladiaceae and the species of Dichotomocladium. A list of families and genera currently included in Mucorales also is provided.