Figure 1. Composite figure outlining the evolutionary relationship between Microlaena stipoides and cultivated rice (Oryza sativa).

Nodal numbers reflect the estimated million years since each bifurcation [4]–[6]. Although O. sativa and M. stipoides shared their last common ancestor approximately 34 million years ago they retain the same base chromosome number, n = 12, similar individual genome sizes [3], endosperm morphology and characteristics [8] and genetic homology [7].