Corona ribbed and frilled.
A description according to West & Fell’s 1941 catalog, “This immense and beautiful pure white trumpet attracted much attention at the 1938 London Show. Very broad, somewhat waved perianth and bold, beautifully fluted and ruffled trumpet; short neck and fine carriage; vigorous grower.”
There are no photos of "Whirlwind" in Daffseek.