The phenomenon that the scientist would hypothesize accounts for the pattern she sees is independent assortment.
Independent assortment refers to the way alleles for different traits separate independently from one another during gamete formation. In this case, the expected offspring ratio from a cross between a double heterozygous (RrGg) and a double recessive (rrgg) would indeed be 1:1:1:1, resulting in an equal distribution of the four possible genotypes (RrGg, rrgg, Rrgg, rrGg).
However, the actual outcome shows a significant deviation from the expected ratios: two genotypes (RrGg and rrgg) appeared much more frequently than the others (Rrgg and rrGg). This suggests that there may be some sort of interaction between the genes affecting the inheritance of these traits, potentially indicating linkage between the flower color and leaf color traits, which would disrupt independent assortment, leading to a non-Mendelian ratio in the offspring.
Thus, she should investigate whether the gene loci are located closely on the same chromosome, causing them to be inherited together more often than anticipated. This phenomenon is commonly known as genetic linkage, which can result in deviations from the expected 1:1:1:1 ratio due to independent assortment being violated.