Mushrooms are the flowering bodies of fungi living in the ground of the field you were floating above. There is a contrast in your dream between yourself, who is floating above the field, and the mushrooms that were the flowers&fruits of environmentally dependent&rooted organisms. You have the ability to move wherever you want, and the other organisms don't. They can only spread over the fields (as the human race has done) by procreation and gradual expansion. But they all Belong in the ground where they have grown up; and you don't have your legs and feet rooted in the ground.
Did you have any sense of where this field might be? Did it trigger any events or memories from your personal history? You are also witnessing the blossoming of their beauty, which completes the fulfillment of their life cycle. You may be able to survey a much wider selection of whole life-histories than any one individual or colony among them; but you don't have your own place among them. You are an observer, but not a participant in their life processes, like a researcher into their species (an Anthropologist if they are humans like yourself).
Does this observer- or researcher-role fit for how you may be feeling with some aspect of your present life?--as floating above the rest of humanity where you are without being in close touch with anyone, and not being rooted in the organic relationship with the ground from which you have grown or producing your own unique beauty like the others seem to be?
Is there anything going on in your present life that might make you feel like you can understand and appreciate more than most people around you, but you were adopted?
This is my interpretation on your dream. I believe the dream is showing you are discovering new aspects about yourself. Floating above something is showing you are being elevated above as to be able to see things in a whole new perspective. Since the mushrooms resembled flowers, this is a whole new part of you and your life you are currently discovering. It is beginning to bloom and become a pleasant aspect of your life.