, Volume 27, Issue 2, pp 187-196

Origin and distribution of polyploid Achillea (Compositae) in western North America

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

The tetraploid and hexaploid cytotypes ofAchillea millefolium in western North America exhibit a complex distributional pattern involving overlapping ranges, mixed populations, and occasional pentaploid, septaploid, and octoploid plants. Cytogenetic and distributional evidence support the hypothesis that there has been a repeated autoploid origin of hexaploids from tetraploid progenitors. It is suggested that chromosome number differences should not be relied on as markers for infraspecific taxa in this complex.

Based on a thesis submitted to Oregon State University in partial fulfillment of the requirements for the Ph.D. degree. Research aided in part by the Northwest Scientific Association, the Department of Botany and Plant Pathology of Oregon State University, and a grant-in-aid of research from the Society of the Sigma Xi. I thank Kenton L. Chambers, James R. Estes, and Friedrich Ehrendorfer, who made his unpublished chromosome counts and interpretations available.