Abstract Abstract Yuccas initiate far more flowers than they can mature as fruit, thereby providing opportunities for them to mature flowers of the highest quality. Flower quality in yuccas has both intrinsic and extrinsic components.
Intrinsic components relate to flower morphology and inflorescence architecture.
In addition, intrinsic and extrinsic components interact as a function of flowering phenology and moth activity within inflorescences. We investigated selective abscission of flowers in Y. kanabensis with respect to various combinations of intrinsic and extrinsic factors. First, we considered the effect of high and low pollen loads delivered to different subsets of flowers and in different presentation orders. In the absence of moth ovipositions, Y. kanabensis is sensitive to the amount of pollen that moths deliver and tends to retain high pollen flowers, even when all flowers receive sufficient pollen for full fertilization. However, pollen delivery sequence and the position of flowers with an inflorescence modify this high pollen effect.