BIOCHEMICAL SYSTEMATICS AND PHYLOGENETIC INTERPRETATIONS IN THE GENUS AQUILEGIA.

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The trend in phytosystematic research is toward the elucidation of phylogenetic relationships. In relatively recent years many schematic representations have been designed to show such relationships. Two of the mos!t recent methods for demonstrating natural similarities are The Wagner Divergence Index (Scora, 1967) and the Simlarity Index Method (Similarity Matrix) (Sokal and Sneath, 1963; Sokal, 1966). Concepts from both of these methods of analysis have been employed in the present study to aid in the determination of evolutionary patterns in the genus Aquilegia. Analytical techniques are similar to those used in the Similarity Index Method. The various species have been grouped on the basis of biochemical affinities which may reflect their phylogeny. The characters examined were drawn from a reservoir of polar compounds including flavonoids and other phenolic pigments. Although a few of the flavonoids could be tentatively identified by comparisons of their properties with those of known compounds listed by Harborne (1967) and Geissman (1962), the identity of the large majority of the pigments examined remains unknown. They have merely been assigned a number and characterized by Rf values, absorption spectra, and physical and chemical properties exhibited under U.V. radiation, both with and without test reagents. The similarity index values were derived through computer programming. Both the divergence index method and the similarity index method are Neo-Adansonian, i.e., all characters are given equal weight. Certainly it is absurd to assume that all characters have equal significance in the determination of phylogeny. However, it has been strongly argued by advocates of the Adansonian system that in the absence of an objective method of character weighing a strictly numerical approach eliminates more bias than it induces. It would seem, however, that the applicability of a numerical approach would depend on the heterogeneity of the characters being considered as well as the degree of affinity among the taxa under investigation. Kendrick and Weresub (1966) have shown that the numerical approach haphazardly assembled, equally weighted characters, results in a haphazard classification at least in higher fungi. On the other hand, using the Wagner Divergence Index, Hardin (1957) and Scora (19,66) devised evolutionary patterns, in the genera Aescu,lus and Monarda, respectively, which correlated very well with previously existing concepts and phytogeographical studies. It is felt that a numerical approach is equally applicable to a phylogenetic analysis of the cytogenetically similar species of Aquilegia, especially when dealing with such biogenetically related characters as the various flavonoid pigments.