Flett's Violet or Olympic Violet, Viola flettii (Violaceae) is an endemic plant of the Olympic Mountains of Washington. It is a small, stemmed perennial herb that grows in rock crevices and talus slopes at subalpine and alpine elevations. Potentially high microhabitat fidelity, complete restriction to certain well developed rock exposures, harsh conditions, small size of most colonies and substantial geographic isolation among them, make this endemic plant prone to extreme inbreeding, strong population subdivisions with low interpopulation-gene flow, and local extinctions. Endemic species have been found to commonly have lower genetic diversity, however species that occur in small sparsely distributed populations have possibly adapted genetic systems to deal with the problem associated with small population size. It is believed that smaller populations of V. flettii will have lower genetic diversity due to inbreeding and random genetic drift, and populations from the higher and lower elevational extremes of the species may also have less genetic diversity. Silica dried leaf material from six populations of V. flettii were surveyed with the Inter-Simple Sequence Repeat (ISSR) markers. There are two genetic groups of the species, segregating as northern and southern populations. In the northern group the population from a spur ridge off Blue Mountain is distinct from another population from Blue Mountain, while the latter intermingles with a small population from nearby Eagle Point. In the south the population from Marmot Pass, the largest population surveyed, has a large amount of genetic diversity encompassing that of the two other southern populations from Mount Townsend and Mount Ellinor. Correlations between genetic data and elevation, geographic distance and ecological data will also be discussed.

Key words: endemic, genetic diversity, ISSR, Olympic Peninsula, Viola