In the present investigation, the distribution and habit of calcium oxalate crystals in Dioscorea japonica Thunb. and Begonia Evansiana Andr. were observed. (1) Distribution of the crystals in Dioscorea which was grown in the field or grew wild on an ordinary soil was examined. They appear at first near the nerve and in the epidermis and then in the mesophyll. Their number in the circle of 650μ diameter increases and decreases after attaining its maximum. In case of ample supply of nutriment, the number is smaller. (2) Effects of absence of particular elements, K, S, N, Mg are observed, in case of Dioscorea, effect of absence of K is not remarkable, while in case of Begonia it is very remarkable. In those cases, distribution of crystals was compared. Also, Dioscorea which grew wild under very bad condition was examined. It may be able to say that deficiency of nutriment increases the production of crystals. (3) In case of Begonia the variation of nutriment may be related to the crystal habit and as indicated in the previous paper, action of NH₄⁺ in forming raphide was observed.