Palynotaxonomy of Brazilian species of Polygala subgenus Hebeclada

This study used pollen morphology to address taxonomic controversies related to several species belonging to subgenus Hebeclada of the genus Polygala (Polygalaceae). According to the last traditionally accepted revision of this subgenus, it comprises 40 species. Nevertheless, a recent taxonomic treatment applying more comprehensive criteria reduced this number to only nine species. Our work focused on 15 traditionally accepted species that occur in Brazil, fourteen of which have been considered as only six species in this recent taxonomic study. Pollen grains from floral buds at pre‐anthesis were collected from herbarium specimens and analysed using both visible light and scanning electron microscopy. Most of the traditionally accepted species were distinguished by different combinations of several pollen‐related features, in particular colpi number (13 or 15), pollen size and shape, and endoaperture type (endocingulate or not) and arrangement (parallel or sinuous). The species accepted in the recent taxonomic treatment could not be discriminated by pollen characters. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157 , 609–619.     

Analysis of lichen substances including triterpenoids by high performance liquid chromatography with a differential refractive index detector and a photodiode array detector

A new method for analysis of lichen triterpenoids was established using high performance liquid chromatography with the combination of a differential refractive index detector (RID) and a photodiode array detector (PDA). It is proved that this method was convenient to detect and identify aromatic and aliphatic lichen substances; it enabled quantitative analysis of substances having no or less absorption of ultraviolet rays such as triterpenoids. In addition, they can be measured in high accuracy compared with the TLC method.     

Stem distribution and clonal structure of Chamaecyparis pisifera growing in an old-growth beech-conifer forest

To elucidate sapling patch formation and the mode of regeneration occurring in Chamaecyparis pisifera, we investigated stem distribution and clonal structure of this species in an old-growth beech-conifer forest in central Japan. The study was carried out in a 1-ha plot using small and large sapling (d.b.h.<5cm, 0.5mheight<2 m and d.b.h.<5cm, height2m, respectively) and adult (d.b.h.5cm) stems of Chamaecyparis pisifera. The numbers of small and large sapling stems were 677 and 149 in the plot, respectively, and they were strongly aggregated. Adult stems occurred at much lower density (90 stems in the plot) and were weakly clustered. Fifty multilocus genotypes at nine allozyme loci were detected among sampled stems. Small and large sapling stems with identical genotypes showed aggregated distribution, while some neighboring adult stems had the same genotypes. Spatial autocorrelation of alleles in small and large sapling stems revealed a strongly positive association among stems within a distance of 10m; but a negative association as distance increased. In adult stems, a strongly positive value was found only in the shortest distance class. These results indicate that clonal growth by layering occurred at the sapling stage and contributed to patch formation. Our results also suggest that the clonal growth by layering is ecologically significant throughout the life history of Chamaecyparis pisifera, particularly as an important strategy for the sapling establishment in the early stage of regeneration process.