Page:Popular Science Monthly Volume 77.djvu/359

Rh

 occurring in the second hybrid generation. This is a uniform and constant type having the short habit of growth and large leaves of the "Havana" parent, combined with the high number of leaves of the "Cuban" parent. It is now grown in the Connecticut River valley and yields 40 per cent, more than the Havana type.

segregation. To take a hypothetical case, suppose two plants are crossed in which the flowers of one are twice as long as the flowers of the other and that this extra length is controlled by three or four separately heritable factors. If only a few of the egg cells can be fertilized on account of dissimilarity from the pollen cells, one would expect only those seeds to be formed that would come from the fusion of the germ cells nearest alike. Intermediates would therefore be more likely to be formed than extremes. There is one other possible way of accounting