Tod F. Stuessy, David M. Spooner, Kayleen A. Evans, Adaptive Significance of Ray Corollas in Helianthus grosseserratus (Compositae), The American Midland Naturalist, Vol. 115, No. 1 (Jan., 1986), pp. 191-197
No takes yet. Share an insight, caveat, or question.
Stuessy et al. (1986) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: