Studies on the nygropetric algal vegetations in the mountains of Kumamoto Prefecture
1971 Volume 32 Issue 2 Pages 27-31
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1971 Volume 32 Issue 2 Pages 27-31
The hygropetric algal vegetations were studied in the mountains of Kumamoto Prefecture in the summer of 1961 and 1962. The source of spray which makes wet the surface of rocks under consideration may be classifyed into three types. The first is the water derived from cold springs in the valley of Naidaijin-dani, and the second is the water from the outflows of the irrigation canals in the valley of the Shakain-gawa. The remaining type of wet rocks is those sprayed by the flows from the rice-fields in the lowermost part of the latter valley. The algal vegetations on these wet rocks may be classified into the following six associations.
1. The lump of gelatinous colonies of blue-green algae represented by Gloeothece rupestris, Gloeocapsa luteo-fusca, Gloeocapsa montana, accompanied by Chroococcus, Aphanocapsa and Nostoc ..........................................................................................................Type 1.
2. Felt-like growths of Scytonema haffmanni var. crassa...............................Type 1.
3. Tufts of Cladophora glomerata...................................................................Type 2.
4. Felt-like growths of diatoms......................................................................Type 2.
5. The long filaments of Rhizoclonium sp.......................................................Type 3.
6. The slimy membrane of filaments of Phormidium autumnale of Ph, corium............................................................................................................. Type 3. When the source of water changes from underground to surface, the blue-green algal colonies are replaced by the green alga as the dominant, and the latter is succeeded by diatoms, Terpsinoe trigetra and Melosira varians. The last stage of successional change is the occurrence of either the long filaments of Rhizoclonium sp. or the slimy membrane of filaments of blue-green algae on the rocks under the overflows rich in nutritive matters from rice-fields. Under such a condition they are in poor development of sheath or gelatinous matters, while those growing under the spring water show a good development of thick gelatinous matter or firm sheath.
