(1927)  Page(s) 25.  
 
This increase in size following the doubling of the chromosomes is a marked feature in many tetraploid varieties that have arisen under cultivation, though not in all. Recently I have found 3 cases of tetraploid varieties in 3 diploid species of Rosa (R. macrophylla, R. cinnamomea and R. indica). In each case the wild diploid species has 14 somatic and 7 gametic chromosomes, while the cultivated tetraploid varieties have 28 somatic and 14 gametic chromosomes. The giant tetraploid varieties are indistinguishable specifically from the wild diploid species, though varietally they differ in size and other minor details.