Population Variation and Introgression in North American Typha

Summary Seventeen Typha populations from the United States were subjected to a detailed analysis of variation in morphology, isozymes (alcohol dehydrogenase and esterase) and fertility. The isozyme data was analyzed using numerical taxonomy. All of the three sets of data were employed in a hybrid analysis of the populations. Little morphological variation was detected compared to isozyme differences in populations of all taxa. The results led to the conclusion that the morphological characters in Typha are tightly linked genetic packages which do not reflect a complex pattern of hybridization and introgression seen more clearly from the biochemical analysis. It was further concluded that hybridization and introgression are important reproductive phenomena between the two species, introgression occuring primarily in the direction of T. angustifolia. The effect of human environmental disruption will be to decrease the abundance of T. latifolia populations and enlarge the distribution of hybrid and introgressant populations.