Koenigia

Abstract: Phylogenetic relationships within Polygonaceae, with an emphasis on Polygonum and segregate genera (e.g., Emex, Persicaria, Polygonella), are investigated using sequence data from the chloroplast gene rbcL. The results show the currently recognized subfamilies are likely not monophyletic. Polygonum as currently recognized is paraphyletic. Three strongly supported clades of Polygonum s.l. were found. Contained within these three clades of Polygonum s.l. are representatives of Atraphaxis, Bistorta, Koenigia and Persicaria. Other strongly supported clades found are Coccoloba, Eriogonum, Fagopyrum, Rumex and Triplaris. Patterns of character evolution were studied by mapping characters onto the phylogeny. A woody habit likely evolved multiple times within the family (in Atraphaxis, Koenigia, Muehlenbeckia, Polygonella and in the ancestor to the Eriogonum–Brunnichia clade). Quincuncial aestivation likely evolved early in the history of the family with four subsequent losses in the Rumex–Oxyria clade, M...

Abstract: Field microenvironments of three annual alpine species, Koenigia islandica, Polygonum confertiflorum, and P. douglasii, were characterized over two growing seasons. Germination, photosynthesis, and growth of all three species were investigated in field and laboratory experiments. The Polygonum species occurred in warm, dry alpine sites which melted out early in the growing season but also dried out early; plants died by mid—August. Koenigia grew in sites which melted out later, but plants remained alive later in the season since their sites did not dry out. Polygonum plants experienced higher soil surface, air, and leaf temperatures than did Kogotus plants. Seeds of the Polygonum species required stratification before they germinated, and light increased germination. Koenigia seeds germinated equally well in light and dark, and stratification was not necessary, although it increased germination percentages. Photosynthetic responses to light were similar in all three species. Koenigia's photosynthetic temp...