Abstract
The algae attached to the stones were studied on the basis of three samples which were collected by Prof. M. TSUDA in the streams in Kauai, the northernmost island of the Hawaiian Islands, in August, 1961.
1. Many species of diatoms, blue-green algae, green algae and Conjugales were found. They are mostly of cosmopolitan species.
2. The diatoms consist of 19 genera, 61 species, 24 varieties and 3 forms (cf. Table 1, Plates 1-3), of which 21 species are cosmopolitan, while the other 40 species are distributed mostly in the warmer regions.
The diatom flora in the streams in Kauai resembles that in the streams of Japan rather than that in the streams in the tropical islands, Sumatra, Java and Bali. (of. HUSTEDT 1938, 1939).
3. WATANABE'S biotic indices of water pollution based upon the species number of Bacillariophyceae were calculated upon the samples from the three stations under consideration ; the values are as follows :
st.1……+118 st.2……+132 st.3……+200
From the above values, the water of the station 1 seems to be slightly polluted ; it may be polluted naturally, not artificially, by fallen leaves, &c. in the woods. The value of the biotic index of the station 2 is nearly equal to the values obtained in the mountain streams of Japan. The station 3 is considerably high, it showing the highest value which can be obtained by this method of biotic index. The flora of diatoms at this station resembles very much that of high moors in Japan.
