II - Experiments on Phyllotaxis - Part III - Diagonal splits through Decussate Apices

Abstract

In the previous investigations of this series (1931, 1933) we operated in certain ways on stem apices of Lupinus albus , and thereby caused big changes in the positions of the subsequent leaves. We concluded that these changes strongly supported Van Iterson’s theory of phyllotaxis (1907), and further that each new leaf arises in the first space that attains both a certain minimum width and also a certain minimum distance below the extreme tip or “growing-point.” But the changes produced did not include a change from a spiral to a whorled phyllotaxis, and consequently they do not answer the question whether the difference between spiral and whorled phyllotaxis depends on some intrinsic difference in the properties of the stem apices, or whether it can be explained in some other way.