As a comment about
Large Cupped Daffodil (Narcissus 'Sentinel'),
jmorth wrote:
Used 4 times as seed parent in further daffodil developments.
This Grant Mitsch hybrid stands straight and lasts long.
The International Daffodil Register & Classified List at
www.rhs.org.uk lists 4 entries w/ this name. the others are division 1(2), and division 7.