SIGMOIDEOMYCES Thaxter, 1891 [Botanical Gazette (Crawfordsville) 16: 22] emend Benny, R.K. Benjamin & P.M. Kirk, 1992 (Mycologia 84:628); 2 species (Benny et al., 1992—monograph and KEY).

Sporulating heads more or less globose, sessile; fertile hyphae coenocytic initially, septate when mature, composed of coiled hyphae that bifurcate, one branch becoming a sterile spine, all sterile spine apices free, and the other continuing to grow; at each branching point, except the last 1 or 2, two stalks are produced each bearing a globose fertile vesicle covered with spores. Merosporangia globose to obovoid, unispored, ornamented, pedicellate. Zygospores unknown. Possibly a haustorial parasite.

Type species: S. dispiroides

Species of Sigmoideomyces:
S. divaricatus McLean, 1923 (Trans. Brit. Mycol. Soc. 8:246) emend. Benny, R.K. Benjamin & P.M. Kirk, 1992 (Mycologia 84:629) (Benny et al., 1992; Mclean, 1923).
S. dispiroides Thaxter, 1891 [Botanical Gazette (Crawfordsville) 16:22] (Benny et al., 1992; Thaxter, 1891).

Sigmoideomyces is similar to Reticulocephalis except that the apices of the sterile spines are free (vs. adherent) and the sporangiolar walls are ornamented (vs. smooth). Sigmoideomyces dispiroides has been collected in northeastern North America whereas S. divaricatus is known from the northeastern United States and the United Kingdom (Thaxter, 1891; McLean, 1923; Benny et al., 1992). As far as is known, no species of Sigmoideomyces has been successfully cultivated.

Benny, G.L., R.K. Benjamin, and P. M. Kirk. 1992. A reevaluation of Cunninghamellaceae (Mucorales). Sigmoideomycetaceae fam. nov. and Reticulocephalis gen. nov.; cladistic analysis and description of two new species. Mycologia 84: 615-641.

Mclean, R.C. 1923. A new species of Sigmoideomyces. Transactions of the British Mycological Society 8:244-246.

Thaxter, R. 1891. On certain new or peculiar North American Hyphomycetes. I. Oedocephalum, Rhopalomyces and Sigmoideomyces n. g. Botanical Gazette (Crawfordsville) 16:14-26.

Updated Apr 09, 2007