EXTENSIVE CLONALITY IN THE ENDANGERED SHRUB HALORAGODENDRON LUCASII (HALORAGACEAE) REVEALED BY ALLOZYMES AND RAPDS

The occurrence of clonality in threatened plants can have important im plications for their conservation. In this study, allozymes and RAPDs were used to determine the extent of clonality in the endangered shrub Haloragodendron lucasii (Haloragaceae), which is known from only four sites within an 8 km range. Allozyme markers identified only six mult ilocus genotypes among the 53 ramets sampled across the four sites, al though a total of 54 different genotypes were possible with the three polymorphic allozyme loci detected. The polymorphic bands detected in the RAPD analysis were capable of producing 2(46) genotypes, but again only six multilocus genotypes were delineated. The allozyme and RAPD data were congruent at three of the four sites. At the fourth site two genotypes were detected by each marker; however, once combined, three multilocus genotypes were observed. The probabilities that the observ ed number of replicates of each combined allozyme and RAPD genotype co uld be generated by sexual reproduction were less than 10(-18), leavin g little doubt that clonality is the explanation for the observed patt erns of genotypes. The genetic conclusions are supported by root excav ations which show potential for vegetative reproduction and the observ ation of no sexual reproduction in the species. The recognition of ext ensive clonality in H. lucasii has had immediate implications for the conservation management of the species and resulted in changes to the management priorities for the species. Thus it is clear that appropria te genetic studies can play an important role in the management of thr eatened species.