Primal Scream is classified as an "Unusual Form" (a.k.a. 'UFO' in the daylily world). An unusual form is defined as: A class of daylilies based exclusively on petal and sepal shapes, not on color or color patterns. The 'Unusual Form' class is made up of 3 types of flower shapes. These include: Crispate, Cascade and Spatulate forms. Primal Scream is a combination of Crispate and Cascade. Many UFOs exhibit various combinations of these shapes. If you're so inclined, you can read more about UFOs at the American Hemerocallis Society website.
Primal Scream came from my friend Roger about 6 years ago. It was part of a trade we made. Primal Scream came home with me in a small white bucket on a drizzly spring morning. It's a hardy, carefree plant that immediately thrived in my garden. I have recently moved it to a prominent location where I can enjoy it on rainy days from inside as well as on sunny days outside. Primal Scream is another one of those "must-have" daylilies. Are you sensing a "must-have" theme?