64 Studies of Inheritance in the Japanese Convolvulus 



insignificant white spots in the five notches of the corolla; moreover, 

 even in one and the same individual, which has very slightly white-' 

 margined flowers, I was able to discern the " hukurin " sometimes clearly 

 but sometimes not at all, according to different stages of their develop- 

 ment, so that it would not be improbable that some plants with such 

 very slightly white-margined flowers were erroneously entered as being 

 without them. Secondly, I have learned by experience that the mode 

 of cultivation has great influence over the production of the " hukurin." 

 Plants were generally grown in a field, but some of them were cultivated 

 in pots, for example a certain number of (c) and (/) in Table III. The 

 difference of the results due to the method of cultivation will be 

 explained by reference to Table IV. 



As will be seen from the above Table, while in the field culture 

 plants with white-margined flowers and those with fully-coloured ones 

 are 74 and 26, respectively, i.e. are almost exactly in the ratio 3 : 1, in 

 the pot culture there are 67 and 33, respectively, i.e. the number of 

 plants with white-margined flowers is relatively much smaller in the latter 

 case than in the former. Plants in (a), (6), (d), and (e) were all cultivated 

 in the field, and we see that here the ratio of the two kinds of plants is 

 nearly equal to 3 : 1 in each case, and the very small deficiency of plants 

 with white-margined flowers from the theoretical expectation in these 

 cases may be probably due to the first of the two causes above mentioned. 

 That in the case of pot culture we see always a definite deficiency, 

 may be perhaps due to the fact that pots are generally too dry in 

 summer without special precautions. As is well known through the 

 investigations of several botanists, the formation of anthocyanin in leaves 

 is very much accelerated when leaves live under very dry conditions. 

 Thus, according to Wheldale^ we see the development of anthocyanin 

 mPelargmiium which was insufficiently watered ; also Miyoshi^ observed 



^ The Anthocyanin Pigments of Plants. Cambridge, 1916, p. 24. 



2 Journ. Coll. Science, Tokyo Imp. University, Vol. xxvii. 1909, pp. 1 — 5. 



