The Distribution of Anthochlor Floral Pigments in North American Coreopsis (Compositae): Taxonomic and Phyletic Interpretations

Abstract

Anthochlors (chalcones and aurones) occur in floral tissues of all members of North American Coreopsis. The genus in North America consists of 46 species distributed in 11 sections, and a total of five chalcone aglycones are found in it. The chalcone butein occurs in all sections, and is the only anthochlor constituent in the closely related woody Mexican sections Electra and Anathysana. These two sections are viewed as primitive. The morphologically distinct but putatively unspecialized woody Mexican section Pseudo‐Agarista sequesters both okanin and butein; the same two anthochlors also characterize two additional sections of herbaceous perennials, Silphidium and Tuckermannia. Sections Euleptosyne and Pugiopappus, comprised of annuals restricted primarily to California, exhibit the rare chalcone stillopsidin in addition to butein and okanin. The remaining four sections, Palmatae, Coreopsis, Calliopsis and Eublepharis are among the more specialized in North America, and are sometimes considered to represent a distinct phyletic line or two related lines. All or some of the members of these sections sequester the very rare chalcone lanceolatin in floral tissues in addition to okanin. Butein is also present in some or all species in each section, and isoliquiritigenin occurs rarely in two sections. Those sections considered more specialized have additional anthochlors relative to primitive sections, and any compound found in a more primitive section also occurs in a more advanced one. Thus, the trend in floral anthochlors in North American Coreopsis is toward increased number of compounds rather than reduction.

Phyletic Trends in Sections Eublepharis and Calliopsis of the Genus Coreopsis (Compositae)

“…It should be emphasized, however, that attempted hybridization between the tetraploid C. linifolia and diploid C. gladiata in the greenhouse was unsuccessful. Anthochlor data (Crawford and Smith, 1983) are neutral on the origin of C. jloridana, neither confirming nor contradicting the plausible derivation outlined above. The large heads of C. jloridana are considered to be secondarily derived.…”

“…Several earlier papers have been published on the study (Smith and Parker, 1971;Smith, 1972Smith, , 1973Smith, , 1974. More recent work has involved leaf flavonoid chemistry of certain species and sections (Crawford, Smith and Mueller, 1980;Crawford and Smith, 1980;Smith and Crawford, 1981), and floral anthochlor chemistry of the North American species (Crawford and Smith, 1983). An overview of the eastern United States and Canadian species (Smith, 1976) and a paper on the sectional relationships (Smith, 1975) have set the stage for consideration of intrasectional phyletic lines in the North American species.…”

Molecular Systematics of Plants

“…By contrast, the hypothesis has been that species in sections Pugiopappus and Leptosyne represent the derivatives of a common ancestor, and no perennial species occur in either section. More detailed redrawn and modified from Smith (1975) and Crawford and Smith (1983a evidence supporting the derived nature of the annuals in Coreopsis will be presented below. The value of restriction site analysis of chloroplast DNA (cpDNA) for inferring phylogenetic relationships in flowering plants has been demonstrated recently in a variety of taxa Sytsma and Gottlieb, 1986a, b;Doeb1ey et al, 1987;.…”

Flavonoid Evolution in Robinsonia (Compositae) of the Juan Fernandez Islands

“…Flavonoids are known to be extremely helpful in some instances in determining systematic and evolutionary relationships in flowering plants (Harborne, 1977;Swain, 1977;Crawford, 1978;Giannasi, 1978;Crawford and Giannasi, 1982;Stuessy and Crawford, 1983). They have been useful particularly in helping to resolve systematic problems in the Compo sitae as evidenced by numerous studies over the past two decades (e.g., Crawford, 1970;Giannasi, 1975;Crawford and Stuessy, 1981;Crawford and Smith, 1983a, b). Flavonoids are especially well-suited for studies in isolated oceanic archipelagoes because the compounds are relatively stable and no special equipment or precautions are needed in the collection of samples.…”