Located on the top of the growing medium. Its mostly inconsequential, and will vanish when the plant grows large enough to deny the mold light to grow. I am putting hydrogen peroxide on it to help in killing it, though it is rather persistent for now since the plants are in a fledgling stage.

EDIT:
Now that the plants are large enough to deny the top of the growing medium any light, the mold has subsided and is now gone.