Clausen, Keck and Hiesey’s studies of clonal transplants during the 1930s and 1940s are famous for demonstrating ecotypic variation. Less appreciated are their studies on natural selection, even though at the time there was little hard evidence of its operation in nature. Here we present new analyses of their study of natural selection in Potentilla (Clausen et al., 1940; Clausen and Hiesey, 19...

Seven pyrrolizidine alkaloids (PAs) have been isolated from Lithospermum canescens and their structures determined by spectroscopical methods. Besides the known lycopsamine, O7-acetyl-lycopsamine and O7-acetylintermedine four new PAs were found. Their structures are O7-(3-hydroxy-3-methyl-butanoyl)-O9-(+)-trachelanthoyl-heliotridine (= O7-(3-hydroxy-3-methyl-butanoyl)-rinderine = canescine), O7...

leaf anatomy of 27 species of potentilla l. (rosaceae), representing 9 sections and four related genera, especially tylosperma botsch., schistophyllidium (juz. ex fed.) ikonn., drymocallis fourr. ex rydb., and sibbaldia l. from iran were studied using light microscopy. the most outstanding characters of blade and midrib were measured. the result revealed a number of taxonomically important char...

As plants have been shown to accumulate organic compounds from contaminated sediments, there is a potential for long-lasting ecological impact as a result of contaminant accumulation in riparian areas of wetlands, particularly the accumulation of non-biodegradable contaminants such as perfluorooctanoic acid (PFOA). In this study, commonly found riparian wetland plants including reeds, i.e., Xan...

The aerial parts of selected Potentilla species (P. anserina, P. argentea, P. erecta, P. fruticosa, P. grandiflora, P. nepalensis, P. norvegica, P. pensylvanica, P. crantzii and P. thuringiaca) were investigated in order to determine their contents of polyphenolic compounds. The results showed that P. fruticosa has relatively high concentrations of tannins (167.3 +/- 2.0 mg/g dw), proanthocyani...