Contrasting levels of genetic diversity between the common, self‐compatible Liparis kumokiri and rare, self‐incompatible Liparis makinoana (Orchidaceae) in South Korea

Levels of allozyme variation and intrapopulation spatial genetic structure of the two terrestrial clonal orchids Liparis kumokiri , a self‐compatible relatively common species, and L. makinoana , a self‐incompatible rare species, were examined for 17 ( N  = 1875) and four ( N  = 425) populations, respectively, in South Korea. Populations of L. makinoana harboured high levels of genetic variation ( H e  = 0.319) across 15 loci. In contrast, L. kumokiri exhibited a complete lack of allozyme variation ( H e  = 0.000). Considering the lack of genetic variability, it is suggested that current populations of L. kumokiri in South Korea originated from a genetically depauperate ancestral population. For L. makinoana , a significant deficit of heterozygosity (mean F IS  = 0.198) was found in population samples excluding clonal ramets, suggesting that pollen dispersal is localized, generating biparental inbreeding. The significant fine‐scale genetic structuring (≤ 2 m) found in a previous study, in addition to the moderate levels of population differentiation ( F ST  = 0.107) and the significant relationship between genetic and geographical distances ( r  = 0.680) found here, suggests a leptokurtic distribution of seed dispersal for L. makinoana . Although populations of L. makinoana harbour high levels of genetic variation, they are affected by a recent genetic bottleneck. This information suggests that genetic drift and limited gene flow could be the main evolutionary forces for speciation of a species‐rich genus such as Liparis . © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 41–48.