Buckwheat is not wheat - and it is gluten free

[guess]

http://celiacdisease.about.com/od/theglutenfreediet/qt/BuckwheatQT.htm

Despite its name, buckwheat is not wheat. It's gluten-free... Buckwheat and wheat are from completely different botanical families. Buckwheat seeds are technically the fruit of a plant called Fagopyrum esculentum.

[guess]

http://en.wikipedia.org/wiki/Buckwheat

Despite the name, buckwheat is not related to wheat, as it is not a grass. Instead, buckwheat is related to sorrel, knotweed, and rhubarb.