16 S. KIKKAWA: 
but in the majority of cases all varieties in one district are sown at nearly 
the same time. 
In this case, however, the time of ripening may of course greatly differ 
according to the variety. Those which ripen early are called early varie- 
ties and those which ripen later are either medium or late varieties. In 
the central part of Japan, the days required for the growth of each of 
these three groups are roughly shown as follows: 
Karly Varieties © re ae nee, . 120—160 
Meditim Tyarıeties tent eee oe eee ed ee 150—180 
Late varieties. ss eee eee eee 170—200 
Of course it is impossible to classifly the rices of the world into such. 
groups; even in one country, where climatic conditions considerably differ, 
such classification is practically useless; but in each district, within 
which the climate is nearly similar, this classification would hold 
good and be found very useful. 
(3) Giant rice. 
The height of the common rice plant hardly exceeds two meters. The 
writer has not had many opportunities to carefully examine foreign rice 
plants in regard to their height; yet from such occasions as he has had 
of observing rice plants standing on fields in certain districts of India, 
Ceylon, Burma, Java and Siam, through which he passed, and a care- 
ful study of many Japanese rices, he has come to the above conclusion, 
The wild rice which is found in deep flooded places of tropical countries 
may attain the height of several meters. In November 1907 the writer 
found wild rice, O. sativa, densely growing in Klon Rangsit about ten 
miles distant from Bangkok, the capital of Siam. As usual after the 
rainy season of that country, the Klon, that is the canal, was filled with 
water about one to one and a half meter deep. The wild plant fixing its 
roots on the bottom of the canal, sends out its stems to the surface of the 
water, to which the stems naturally kept their position obliquely, because 
they were always forced to bend to the flow of water. 
