Table 3 . Divergence times for grass clades on the basis of the rht1 data set.

Species Comparison	Subfamily/Tribe Comparison	Mean divergence time in millions of yearsa (Upper and Lower 95% Confidence Interval)
Zea mays – Triticum aestivum	Panicoid – Pooid	57.36 (37.32–5.92)
Zea mays – Eragrostis tef	Panicoid – Chloridoid	36.47 (20.64–50.54)
Zea mays – Setaria italica	Panicoid: Andropogoneae – Paniceae	26.86 (13.70–38.71)
Zea mays – Sorghum bicolor	Panicoid: Andropogoneae	14.20 (6.57–22.04)
Zea mays – Tripsacum dactyloides	Panicoid: Andropogoneae	7.20 (1.92–12.56)
Sorghum bicolor – Saccharum officinalis	Panicoid: Andropogoneae	6.00 (1.63–10.23)
Setaria italica – Pennisetum glaucum	Panicoid: Paniceae	7.90 (2.02–13.61)
Triticum aestivum Brachypodium distachyon	Pooid	40.72 (18.85–63.03)
Triticum aestivum – Hordeum vulgare	Pooid	18.19 (4.44–28.96)
Eragrostis tef 1 – Eragrostis tef 2	Chloridoid	6.38 (1.51–11.77)

^aDates are based on a fossil divergence date of 55 million years for the divergence between Zea and Oryza.