Hilda M. Canter

Studies on British Chytrids: VI. Aquatic synchytriaceae

Summary The morphology and life history of seven aquatic Synchytriaceae are described. Micromyces zygogonii Scherffel, M. petersenii Scherffel and Micromycopsis fischeri Scherffel are new records for Great Britain; Micromyces laevis, Micromycopsis intermedia and M. mirabilis are new species; and Endodesmidium formosum gen.nov. sp.nov. In Endodesmidium the sporangia emerge from the sorus as non-swarming zoospores, and it is believed this represents a primitive condition within the group. References to ‘asterospheres’ in the older British literature are cited, and the validity of records of Micromycopsis and Micromyces spp. are considered.

Studies on British Chytrids: II. Some new monocentric chytrids

Summary Five monocentric chytrids are described growing on algae from Great Britain. Of these, three are new species, namely, Phlyctidium apophysatum, Rhizidium variabile and Chytridium cocconeidis. Chytridium versatile var. acaulis represents a new variety, and a species of Rhizophidium is identified with Rhizophidium globosum Scherffel (1926) .

Studies on British chytrids: IV. Chytriomyces tabellariae (Schröter) n.comb. parasitized by Septosperma anomalum (Couch) Whiffen

Summary Two parasitic chytrids, both new records for Great Britain, are described. Phlyctidium tabellariae Schroter is found to be operculate and is transferred to the genus Chytriomyces Karling; the name becomes C. tabellariae Schroter n.comb. Septosperma anomalum (Couch) Whiffen was found parasitizing C. tabellariae.

On Aphanomycopsis bacillariacearum scherffel, A. desmidiella n.sp., and Ancylistes spp. in Great Britain

Summary Aphanomycopsis bacillariacearum has been found in Pinnularia sp. from Blelham Bog, near Wray Castle, and a new species Aphanomycopsis desmidiella is described parasitizing the desmid Netrium digitus. Ancylistes is recorded for the first time from Great Britain and the presence of a conidial stage is confirmed. Tetmemorus granulatus Breb. is a new algal host for this parasite and the emergence of external hyphae at the junction of the two semi-cells of the desmid has not formerly been described.

Studies on British chytrids: V. On Olpidium hyalothecae Scherffel and Olpidium utriculiforme Scherffel

Summary Olpidium hyalothecae Scherffel and O. utriculiforme Scherffel are recorded for the first time in Great Britain.