||Christin PA, Besnard G, Samaritani E, Duvall MR, Hodkinson TR, Savolainen V, Salamin N. Oligocene CO2 decline promoted C4 photosynthesis in grasses. Curr Biol. 2008 Jan 8 18(1):37-43PubMed ID18160293
||Researchers inferred a large phylogenetic tree for the grass family and estimated, through Bayesian molecular dating, the ages of the 17 to 18 independent grass C4 lineages. The first transition from C3 to C4 photosynthesis occurred in the Chloridoideae subfamily, 32.0-25.0 Mya.
||C4 plants came to dominate certain terrestrial ecosystems only 8–5 Mya, emphasizing the possible minor ecological importance, at a global scale, of C4 grasses during the first 10–20 My of their evolutionary history (appearance of C4 plants, 25-32 Mya BNID 105193).