Daniel J. Crawford, Jeffrey D. Palmer, Marilyn Kobayashi, Chloroplast DNA Restriction Site Variation, Phylogenetic Relationships, and Character Evolution Among Sections of North Americn Coreopsis (Asteraceae), Systematic Botany, Vol. 16, No. 2 (Apr. - Jun., 1991), pp. 211-224
No takes yet. Share an insight, caveat, or question.
Crawford et al. (1991) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: