Archangiopteris itoi, an endemic fern in Taiwan, is under threat due to hum
an disturbance. Based on fossil evidence the origin of Archangiopteris can
be dated to the Middle Jurassic Age. Field survey indicated that only eight
een individuals were left in the wild. The population at Lienhwachi, on whi
ch the species was named, is now extinct. The genetic variation of the popu
lation remaining at Wulai was assessed by RAPD fingerprinting. Of 40 oligo
primers, only one revealed polymorphism. Nevertheless, this primer enabled
identification of six haplotypes. The low variability within the population
is ascribed to the small population size, which was constrained largely du
e to habitat disturbance. In the small population, genetic drift will have
greater effects leading to loss of variation at most loci. In this study, R
APD data indicated that some variation existed within the population, thus
suggesting that materials were available for re-establishment of the popula
tions.