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Chromosome Counts Of Compositae From Mexico And The United States, David J. Keil
Chromosome Counts Of Compositae From Mexico And The United States, David J. Keil
Biological Sciences
Chromosome counts of Compositae are reported from Mexico and the United States. First generic counts are from Egletes (n = 27), Hydropectis (n = 9), and Pippenalia (2n = ca. 60). First counts also are reported for 22 specific and infraspecific taxa in Baccharis, Erigeron, Flaveria, GnaphaUum, Grindelia, Helenium, Heterotheca, Melampodium, Montanoa, Perymenium, Piqueria, Senecio, Stevia, Verbesina, Xanthocephalum, and Zaluzania. Additional counts also are provided for 123 populations of taxa counted previouslY, of which eight are new numbers. Taxonomic implications of certain counts are discussed.
Chromosome Counts Of Compositae From The United States And Mexico, Donald J. Pinkava, David J. Keil
Chromosome Counts Of Compositae From The United States And Mexico, Donald J. Pinkava, David J. Keil
Biological Sciences
Chromosome counts are reported for 126 taxa representing 122 species and 61 genera of Compositae. First reports include two genera, Stylocline (n = 14) and Chromolepis (n = 19), 17 species, two infraspecific taxa, and one interspecific hybrid. Five additional taxa have chromosome numbers differing from previously published accounts. Carminatia is reinstated to generic status.
Clematis Coahuilensis (Ranunculaceae), A New Species From North-Central Mexico, David J. Keil
Clematis Coahuilensis (Ranunculaceae), A New Species From North-Central Mexico, David J. Keil
Biological Sciences
Floristic investigations in the Cuatro Cienegas basin and nearby mountain ranges in Coahuila, Mexico, have resulted in the discovery of a previously undescribed species of Clematis (Ranunculaceae). The new species, Clematis coahuilensis, is apparently restricted to the Chihuahuan Desert Region and adjacent segments of the Sierra Madre Oriental. Its known distribution is centered in Coahuila.
Chromosome Studies In North And Central American Species Of Pectis L. (Compositae: Tagetaea), David J. Keil
Chromosome Studies In North And Central American Species Of Pectis L. (Compositae: Tagetaea), David J. Keil
Biological Sciences
Chromosomal modification is often a major factor in the evolutionary diversification of a large, rapidly evolving genus. Pectis, the largest and most widespread genus in the New World tribe Tageteae (Compositae), has radiated into a variety of habitats during its evolutionary history. Until relatively recently, however, little has been known of the role of chromosomal change in the evolution of the genus. Pectis was cytologically unknown until the studies of Raven and Kyhos (1961) and of Turner, Ellison, and King (1961). Subsequently, additional counts have been reported for several taxa (Table 1). To date, however, only a few of …
Revision Of Pectis Section Pectidium (Compositae: Tageteae), David J. Keil
Revision Of Pectis Section Pectidium (Compositae: Tageteae), David J. Keil
Biological Sciences
Pectis L. sect. Pectidium (Less.) A. Gray is a small but very wide-ranging group of taxa. The geographic range of this section includes both insular distribution patterns and broad disjunctions. In an effort to clarify the systematic relationships and to provide a possible explanation for the interesting distribution patterns, I undertook an investigation of this section.