Contributions to our knowledge of indian algae-III. Euglenineae-Part-I. The genus Euglena Ehrenberg.

An account of 29 taxa comprising 24 species and five varieties of the genus Euglena collected from various localities in north-east, central and south India during 1937-76 is given. Of these, two, viz., E. vaginicola and E. pseudoehrenbergii have been considered as new species, one, viz., E. viridis var. maxima a new variety and one, viz., E. tuba var. pseudotuba f. minima a new form of a new combination variety. Four species, viz., E. vagans, E. helicoideus, E. granulata and E. hemichromata and three varieties, viz., E. tripteris var. klebsii, E. oxyuris var. playfairii and E. caudata var. minor appear to be new records for the Indian region. By studying the taxa from different ecological habitats it is shown that there is considerable variation within species in E. acus and E. tuba and to a limited extent in E. oxyuris. Since E. ehrenbergii as known at present is a composite species, E. srinagari has been separated from it, following Huber-Pestalozzi in this respect. E. tuba Carter which had been incompletely known so far and considered by most authors as doubtful, was studied in detail and shown to be a well defined species needing an emended description. E. tuba johnson, which shows some essential differences from Carter's species, is treated as a variety of E. tuba, viz., var. pseudotuba with an Indian form which is new. There is also a possibility of polymorphism in E. tuba. Meteorological and water conditions under which some of the species dominated are given. It is also shown that some species are characteristic of particular habitats. The need to give all relevant details including proper illustrations while describing the taxa of this difficult genus is stressed. The author has made an attempt to fill the, gaps in existing descriptions of the Indian taxa given in this paper to help in proper identifications. A key to these taxa is also given. A list of 29 other species reported from India by other workers is given with references and localities. [ABSTRACT FROM AUTHOR]