I think your "first grass" date is incorrect. Wikipedia says there are grass fossils over 100 million years old: https://en.wikipedia.org/wiki/Poaceae#Evolutio

I think your "first grass" date is incorrect. Wikipedia says there are grass fossils over 100 million years old: https://en.wikipedia.org/wiki/Poaceae#Evolutionary_history https://en.wikipedia.org/wiki/Poaceae#Evolutionary_history