A CHEMOTAXONOMIC STUDY OF BAPTISIA LEUCOPHAEA VAR. LAEVICAULIS (LEGUMINOSAE)

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Abstract
A comprehensive chromatographic study of Baptisia leucophaca var. laevicaulis was carried out. with particular emphasis upon intraspecific variation in phenolic compounds within a single population, among populations representing the range of the species, and at different developmental stages. In addition, more limited analyses were made of alkaloids and free amino acids. Among phenolic compounds the patterns were generally consistent; hence they were reliable species indicators. Some individual variation among phenolics occurred within the population which was selected for most complete analysis. In addition, 2 chemical races were disclosed, represented in a series of geographically contiguous populations. These chemical races did not correlate at all in their distributions with previously recognized morphologically distinct subspecies or varieties. No attempt was made to give formal recognition to the chemical races. The species B. bracteata, an east‐coast taxon resembling closely B. leucophaea, was chromatographically indistinguishable from B. leucophaea, and despite the widely divergent allopatric distribution of these taxa, the genetic differences separating them may be slight. Contrary to expectations, the individual differences and developmental changes in alkaloids of different plants were so great that at present these compounds cannot be utilized as markers in interspecific hybridization. In contrast, the free amino acids of all plants investigated yielded closely similar distribution patterns, and the amino acid patterns of leaves, flowers and even seeds were generally quite similar. The chromatographic studies did not support the recognition of separate species within the Baptisia leucophaea complex of Texas and adjacent states. While B. minor, B. nuttalliana, B. sphaerocarpa and B. leucantha are clearly distinct chromatographically from B. leucophaea, in contrast, B. laevicaulis, B. cuneata and B. bushii were indistinguishable from B. leucophaea.
Funding Information
  • National Science Foundation (15892)
  • National Institutes of Health (11111–01)