1. The favourable conditions for the development of Chromatium gracile and Chromatiumminus are given in the following table. 2. Among the Chromatium found in Japan, Chromatium gracile, Chromatium minus and Chromatium weissei develop well in the culture medium to which acetic-succinic acid, glucose or glycerin are added as the carbonic acid source in place of sodium bicarbonate. Only in the development of Chromatium gracile formic acid is used. Also with Chromatium gracile either acetic- or succinic acid is used as a hydrogen denoter in place of sodium sulphide; yeast and cystein being used too.
1) The sexual reproduction by the biflagellate gametes of a Prasiola species, which is probably Prasiola japonica Yatabe, was discovered. 2) Formation of the round thick-walled gonidia and the microscopic crenated gemmae are discovered on the margin of the frond grown out of zygote. 3) By the experiment of germination of zygotes which are made to attach to a stone, remarkable increase by asexual reproduction is ascertained. 3) Enlarged round gonidia are extruded as the naked undivided aplanospores (av. 13μ in diameter). The mode of germination of aplanospores is the same as that of the full-grown zygotes. This feature is different from the “tetraspores” (6-8μ in diameter) reported by Lagerheim which have already undergone vertical and horizontal divisions. The fronds grown out of the cultured zygotes get perforated after losing the aplanospores and eventually disappear from September to October. 5) The fronds derived from the aplanospores form also the aplanospores on the margin, and this may be repeated. Finally the gametangia are formed. In late November they begin to liberate the gametes. 6) Young fronds and the microscopic sporelings are found chiefly from April to November. Even a young frond which measures about 1cm in length already has the aplanospores in the best condition. 7) Increase of Prasiola is mainly due to asexual reproduction. From July to November they go on in quantity. 8) Although there are both sexual and asexual reproduction in Prasiola, alternation of nuclear phase may not exist, since the gametes are liberated from the frond just forming aplanospores. 9) The life-history of Prasiola in the Mitsusawa is considered as follows: ‘The zygotes begin to germinate after increasing in size. The growth of their sporelings continues, forming aplanospores on its marginal parts. After the asexual reproduction by aplanopores has been repeated, the gametangia are formed on these fronds. The liberation of the gametes extends from late October to late April next year, then they lost from sight. But by this time the fronds derived from the zygotes are already growing.’
1. Carices of this region are much more connected to the outer regions through Saghalien than the Kurile Isls.. 2. The Kurile Isis. may be divided into three districts on the phytogeographical point of view. 3. Some Saghalien species are found in south-eastern Hokkaido or Isl. Shikotan, and the species existing in Honshiu are partly found only in the central to eastern Hokkaido. 4. La Perouse Strait and Tsugaru Strait divide the distributions, but not so evidently. 5. Quelpaert are more closely related to Japan than the Korean peninsula. 6. Some species grow in Central China, (Southern Korea) and Japan. 7. Utricles float for a long time, showing the most important factor for the distribution, and the sea currents are useful for this purpose. 8. The distributions have much references along with the climatic and edaphic conditions since Tertiary period, and also width of habitats in respective species. 9. Some Australian species resemble those of this region, and the endemic species in the small islands show remarkable features. These facts suggest us the formation of the new species of Carices rather in short times.