Wtf, I was taught about grains and stuff in primary school. How is that possible when we were both taught the same national curriculum?
I don't think anyone overly checks what primary schools are teaching. There aren't exactly any exams, (bar SATs), so primary schools get a pretty much free-reign to teach specific things as they see fit.
Like, we learnt about vegetables, fruits, plants, flowers, pollination, food groups, etc... But there wasn't anything specifically on grains, bar them being a big part in the food groups. Nothing to teach that they're grasses, or fruits, nor all the different types of grain.
And while we knew of grains, I suppose the likes of wheat and barley were more prevalent than corn.
For starters, my primary school was in the South West, where there are farms everywhere, and everyone had seen a field of wheat.
And, although it may not impact on it, my primary school was a Church of England school, so there was probably some skimming of time from other subjects to teach RE and give religious assemblies and visits to the church.