An analysis of the relative abundance of the prevalent species in 25 major plant communities of the Wasatch Mountains demonstrates that variation in species diversity is significantly correlated with many floral characteristics. Wind pollinated flowers decrease in abundance while animal pollinated flowers increase along the diversity gradient. Both relationships are highly significant statistically. Color diversity and species diversity are significantly and positively correlated in open communities but are not correlated in forest communities. The percent sum frequency of yellow and pink-magenta flowers decreased with increasing species diversity while blue and whitish flowers increased. Also, zygomorphic flowers and flowers in which access to the nectar supply is restricted by morphological barriers are positively correlated with species diversity. It is shown that wind pollinated flowers and entomophilous open flowers are significantly more abundant than animal pollinated flowers whose nectaries are morphologically restricted, Theoretical explanations are offered for these relationships.