The study of the algal flora of the rice fields in tropics has attracted considerable attention. FRITSCH (1907 a, b), HOLSINGER (1935), BANERJI (1935), DE (1939), SINGH (1939, 1961), WATANABE (1959WATANABE ( , 1962) ) and others have studied the algae of the paddy fields in India and abroad. The observations however are confined either to algae appearing in soil culture or to those collected during a particular time of the year.
The present investigation was undertaken sometime ago with a view to study the succession of algae in some of the paddy fields of Allahabad District (India), and to correlate the growth of the algae in nature with the growth found in culture of the soil samples collected from these fields.
A plot of about 2 sq. miles was selected for this purpose in which rice alone is cultivated from year to year. Two varieties of rice are sown. The early variety is sown in the beginning of July in fields which are at higher level and will be referred to as upland fields. It is harvested in September and the fields lie fallow during the rest of the year. The late variety is transplanted in August in the low lying fields to be called low-land fields. These remain water logged for a considerable time. The crop is harvested at the end of November or early in December and the fields are therefore not available for the second crop.
Both the methods of soil culture and that of direct observation * Read at the annual meeting of the Sci. and Techn. Society, Kanpur, Dec.