[From The Art of Gardening with Roses, by Graham Stuart Thomas, p. 50: petals are] arranged into radial sections.
[From Roses by Susan Bales, p. 47:] so many petals tucked into a cup shape that the petals stand straight up flattened against each other. The petals form a scalloped arrangement that seems to divide the flowers into four equal parts. The top of the flower is so flat that it appears to have been sliced off with a sharp knife.