* Mealies is a regional term: It's mainly used in South Africa and other parts of Africa. This means it's less common in other English-speaking regions, making a specific collective noun less likely.
* Corn is typically singular: We usually talk about a "field of corn" or "a cob of corn," rather than using a collective noun for the grains themselves.
Possible alternatives:
* Earful of mealies: This is a playful, informal way to refer to a large quantity.
* A pile of mealies: This is a straightforward description.
* A basket of mealies: This is specific to the way they are stored.
Ultimately, the best way to describe a group of mealies depends on the context and the desired tone.