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Pteris cadieri (Pteridaceae) exhibits significant morphological variation, its fronds range from simply pinnate to bipinnatifid. The morphological characteristics of P. cadieri and P. grevilleana vary along a continuum and suggest that P. cadieri is a hybrid species and P. grevilleana is a potential parent species. However, previous studies do not provide evidence to support or refute this hypothesis. To explore this hypothesis of hybrid origin, the reproductive biology of P. cadieri and P. grevilleana was studied in Taiwan. There were diploid and triploid P. cadieri, but P. grevilleana was diploid. All plants of both species were apogamous. In both species, spore shape varied (tetrahedral, globose, ellipsoidal) and germination rate varied, the first frond of some juvenile sporophytes had a midrib, and polyembryony occasionally occurred, the latter being the first report of polyembryony in apogmous ferns. Variation in spore number per sporangium, spore size and spore shape indicated abnormal sporogenesis. All these traits suggested that P. cadieri and P. grevilleana are of hybrid origins. However, the hypothesis that P. grevilleana is a parent of P. cadieri should be reconsidered. [ABSTRACT FROM AUTHOR]

The genotypic compositions of two populations of the brooding coral, Pocillopora damicornis, were studied by exhaustive sampling of adult colonies on a fine scale in southern Taiwan. In addition, 100 larvae were randomly selected among more than 1,000 brooded larvae collected from a single broodparent within each population. Using 7 polymorphic microsatellite markers, both populations were found to be highly clonal, and 7 clonal lineages were characterized. One clonal lineage (C1) dominated both study areas and comprises 54.9% of all colonies sampled, while any of the other 6 clonal lineages represented no more than 5%. Among the 100 larvae randomly selected for genotyping from each broodparent, the extent of clonal reproduction was high, and only 29 and 6 larvae, respectively, were found to be genotypically different from their broodparent. Among the 35 genotypically distinct larvae, 33 were thought to be derived from sexual reproduction, and 2 were assumed to be clonal propagules that had undergone somatic mutations. Two genotypically identical larvae were also found in one of the 2 sexually derived larva arrays, indicating the possible existence of polyembryony. The high proportions of clonality in both adult colonies and brooded larvae suggest that asexually produced larvae might significantly contribute to the recruitment of local populations. The dense clonal population of P. damicornis in the study area favors the quick recolonization view of clonal propagules after disturbances. [ABSTRACT FROM AUTHOR]