Isozyme variation in Sisyrinchium sarmentosum (Iridaceae)

Sisyrinchium sarmentosum is a rare, duodecaploid plant endemic to the Mt. A dams and Mt. Hood areas of Washington and Oregon. Isozyme variation in six Washington populations was assessed to infer genetic variation in this spec ies. Five of the six sampled populations were monomorphic for the sixteen e nzymes surveyed, although at one putative locus one of these populations wa s monomorphic for an enzyme band pattern not seen in any other population. The sixth population had low levels of variation in two enzymes. This low l evel of variation has often been observed in very rare species and high pol yploids. Apparently, the species has recently gone through a bottleneck, pe rhaps during its recent origin as a species.