Corn

Bare corn cobs (without the kernels) were ground, put through a sieve, mixed with ground or crushed leaves of trees, and water (or milk, if there was any), and made into flat-cakes.

Corn stalks were dried, ground, put through a sieve, mixed with water and used for baking flat-cakes.

Such "cornmeal" was also cooked in boiling water to make porridge.