Key points are not available for this paper at this time.
Michael J. Donoghue, Richard G. Olmstead, James F. Smith, Jeffrey D. Palmer, Phylogenetic Relationships of Dipsacales Based on rbcL Sequences, Annals of the Missouri Botanical Garden, Vol. 79, No. 2 (1992), pp. 333-345
Donoghue et al. (Wed,) studied this question.