The flower size varies, increasing from southeast to northwest, correlating with plant size, probably reflecting a rainfall gradient from the hot
Mediterranean climate of the southeast to the cooler, wetter Atlantic climate found in the northwest. Changes in flower size correlate with pollinator fauna,
Anthophora species being dominant in the southern population and the larger-bodied
Bombus species in the north.
Self-pollination was found to result in significantly lower seed production than in
cross-pollination within
Narcissus triandrus. == Distribution and habitat ==