Found on The Goddess & the Green Man website … a really great place! Check them out!

The Grain Mother.
At Lammas the Goddess is in Her aspect as Grain Mother, Harvest Mother, Harvest Queen, Earth Mother, Ceres and Demeter. Demeter, as Corn Mother, represents the ripe corn of this year’s harvest and Her daughter Kore/Persephone represents the grain – the seed which drops back deep into the dark earth, hidden throughout the winter, and re-appears in the spring as new growth. This is the deep core meaning of Lammas and comes in different guises. The fullness and fulfillment of the present harvest already holds at its very heart the seed of all future harvest. (It is a fact that a pregnant woman carrying her as yet unborn daughter is also already carrying the ovary containing all the eggs her daughter will ever release – she is already both mother, grandmother and beyond, embodying the great Motherline – pure magic and mystery.)
So as the grain harvest is gathered in, there is food to feed the community through the winter and within that harvest is the seed of next year’s rebirth, regeneration and harvest. The Grain Mother is ripe and full, heavily pregnant she carries the seed of the new year’s Sun God within her. There is tension here. For the Sun God, the God of the Harvest, the Green Man, or John Barleycorn, surrenders his life with the cutting of the corn.