シロツメクサ
"Trifolium repens" is a tetraploid (4n=32) with two diploid ancestors. In order to increase genetic diversity for breeding, research is focused on finding these ancestors. Proposed ancestors of "Trifolium repens" include "Trifolium nigrescens, Trifolium occidentale, Trifolium pallescens," and "Trifolium uniflorum."" " Additionally, it is possible that one of the diploid ancestors has yet to be analyzed, either because it has not been discovered or is extinct.