Thing I learned on the internet this morning: Though the yellow color is present in the leaf throughout the growing season, chlorophyll masks the pigments known as xanthophylls. This hue becomes visible when the green chlorophyll is gone.

Thing I learned on the internet this morning: Though the yellow color is present in the leaf throughout the growing season, chlorophyll masks the pigments known as xanthophylls. This hue becomes visible when the green chlorophyll is gone.