CLONAL DIVERSITY IN ALPINE POPULATIONS OF POLYGONUM-VIVIPARUM (POLYGONACEAE)

Asexual reproduction is extremely common among arctic and alpine speci es, and successful sexual reproduction may be rare. In asexual populat ions, the absence of segregation and recombination predicts reduced le vels of genetic variation. Thus, genetic diversity within arctic and a lpine plant populations may be quite low. Allozyme analysis of three a lpine populations of Polygonum viviparum, a common herbaceous perennia l with no observed sexual reproduction, revealed surprising levels of genetic diversity. There were 23 unique clones within a sample of 150 ramets. Few clones were large or distributed among all three sample po pulations; the majority of clones was rare (n less than or equal to 5) and unique to a single population. Genotypic diversity differed among the three sample populations. The number of clones and measures of di versity and evenness were much lower in the fell-field population than in wet meadow and dry meadow populations. Overall, genotypic diversit y and structure of alpine P. viviparum are similar to other clonal spe cies in which sexual reproduction is rare, and they are similar to the average for clonal species in general.