Here is the link to the definition on the AHS terms page. There are photos there to show examples. It is a form of sculpting. The examples shown are of "midrib cristating."
http://www.daylilies.org/ahs_d...
"A form of sculpting that refers to appendages of extra petal tissue growing from the midrib or elsewhere on the surface of the petals. When the extra tissue grows from the midribs, the form is called Midrib Cristate."
