Preliminary Chromatographic Studies of Laphamia and Related Genera of Compositae

Abstract

In an effort to acquire further data relevant to the taxonomic status of Laphamia and Perityle, 2 genera which have been combined by some workers, and in an attempt to establish further criteria for the recognition of species of Laphamia, a chromatographic analysis of some species of these taxa was undertaken. Methods were devised which gave good separation and resolution of the phenolics characteristic of these species. A number of flavonoids, many of which appear to be flavonol glycosides, are present. Most species of Laphamia and Perityle can be distinguished on the basis of the chromatographic patterns. The chemical evidence is useful in evaluating the taxonomic status of Laphamia and Perityle. Chromato- graphic patterns of certain species of Laphamia are quite similar to certain of those of Perityle. Both Laphamia and Perityle are quite distinctive chromatographically from another genus, Pericome, which on the basis of its morphic similarity to Laphamia and Perityle has been suggested as a close relative. The genus Laphamia Gray (1852) was said by its author to be pos- sibly closely related to Perityle Benth. Distinctions of the two genera involved mainly technical details of pappus-form. However, certain taxa exhibit intermediate pappus-forms, and Johnston (1941), Everly (1947) and Shinners (1959) have questioned the usefulness or even the naturalness of the generic separation. Shinners merged the two genera. The present work was undertaken to acquire chemical data which (1) might disclose further similarities or dissimilarities of Laphamia and Perityle, (2) might be valuable in the necessary rein- vestigation of the alignment of species within these genera, and (3) might be useful in the recognition and circumscription of species. For clarity of exposition, the two generic names will be retained in the present discussion. Chromatographic techniques were developed to provide supplementary characters which might prove to be useful as indicated in exploring the problems outlined above. Similar techniques have proven useful in other instances (Alston and Turner, 1963a; Harney and Grant, 1964; Levin and Smith, 1965). Approximately 25 species of Laphamia are known. About 12 species occur in the area from New Mexico west to California and 13 addi-