The results of investigations on the hot springs at Tuwa are incorporated in this paper, which is the fifth in the series (cf. THOMAS & GONZALVES, 1965 ; 1965 a, b, and c) on the algal flora of the hot springs of Western India . Tuwa is a village on the Anand-Godhra line of the Western Railway, about forty miles from Anand in Gujerat State . A total of 109 taxa has been recorded from these springs (44 diatoms, 64 members of the Cyanophyceae and one member of the Chlorophyceae). These include three new species, two new varieties and two new forms . The specimens are preserved in the Blatter Herbarium, St . Xavier's College, Bombay .
Many springs occur at Tuwa within an area of approximately 440 square metres . The most prominent spring erupts into a central tank which is divided into four equal parts . Around this tank are situated eight other tanks 0 .62 x 0 .62 metres in dimension . In addition, several earthen pots forming basins of hot water have been fixed in this area. The temperature of these pools varies from 25ยฐC to 65ยฐC . The flow of water is about 2,500 litres per hour . The algae grow fairly vigorously in these pools . The springs were visited thrice during the years 1958-1961, in the months of November 1958, June 1960, and January 1961 . The taxa marked with an asterisk have been recorded and described earlier by the authors in other hot springs . Diatoms, when reported above 52ยฐC were observed only in the non living condition . BACILLARIOPHYCEAE 1 . Melosira islandica 0. MULL. var . helvetica 0. MULL . At 38ยฐ C, 48ยฐC, and 60 .5ยฐC .
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Melosira grnaulata (EHR.) RALFS var . angustissima 0. MULL .* At 51ยฐC .
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Cyclotella meneghiniana KUTZ . var . rectangulata GRUN .* At 32ยฐC . 4. Cyclotella meneghiniana KUTZ . var . plana FRICKE*