If you were wondering.

"The people of northeastern North American were among those who recognized the symbiotic relationship between corn, beans, and squashes: the bean climbs the natural trellis of the corn stalk, while the squash shades the ground below, discouraging other plants from spreading and choking the corn roots. Each plant also gives and takes different nutrients from the soil. The people of the Iroquois Confederation called these crops the Three Sisters, or the sustainers, because of their importance to the well-being and survival of the people."

-from this book.