From the sign at the base of the plant.
"Look Inside"
"This half-dome form allows you to see what is inside a traditional Thousand Bloom chrysanthemum.
It showcases the single stem, complex metal framework and the labor-intensive tying technique that makes this form so spectacular"
I have moved the picture of the Thousand Bloom chrysanthemum and the two 500 bloom plants in the gallery so they are adjacent to this picture for clarity of the explanation.