The cytogeography of Aster lanceolatus. III. Cytoecology in southern Ontario

Abstract

Aster lanceolatus Willd. is represented by five polyploid levels in southern Ontario: tetraploid (2n = 32), pentaploid (2n = 40), hexaploid(2n = 48), heptaploid (2n = 56), andoctoploid(2n = 64). Tetraploids were absent from the Niagara Peninsula in the southeast and Essex County, Kent County, Lambton County, and Elgin County in the southwest, whereas the hexaploids were ubiquitous. Correlations were found between chromosome number and habitat (community type), water content of the soil, physiographic region, and grouped physiographic region. These correlations notwithstanding, the distribution of the two predominant cytotypes in southern Ontario may also be related to historical factors.