The hybrid of nos. 1 [Narcissus pseudonarcissus L.] and 2 [Narcissus poeticus L.] ) with the corona only half as long as the tep, and N. jonquilla L., the jonquil, with 2-6 yellow fls 2-4 cm wide, the corona less than a fourth as long as the tep, rarely escape.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.