Comparative molecular systematics of North American Plants with the main emphasis on cool-temperate and boreal Asiatic elements

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Molecular systematic analyzes, phylogenetic relationships, and genetic affinity of various North American as well as Japanese cool-temperate elements of Arcto-Tertiary origin were stduied in a two-year period 1996 thorough 1997.(1) matK gene of cpDNA were sequenced and their phylogenetic relationships were analyzed for the following groups, with the main emphasis on the members of Liliiflorae and Magnolia : Trillium (37 spp.), Uvularia (5 spp.), Erythronium (15 spp.), Lilium (37 spp.), Notholirion (1 sp.), Nomocharis (2 spp.), Fritillaria (15 ssp.), Medeola (1 sp.), Scoliopus (2 spp.), Convallaria (1 sp.), Clintonia (5 spp.), Tulipa (2 spp.), Veraturum (1 sp.), Cardiocrinum (1 sp.), Magnolia (25 spp.), Michelia (2 spp.), Liriodendron (2 spp.). The sessile group of Trillium subgenus Phyllantherum formed one conspicuous clade, as expected, but T.grandiflorumand T.ovatum proved to represent a sister group, paraphyletic to the former group. T.undulatum, T.pusillum, and T.govanianum are par … More aphyletic to the remaining group of the genus. Many new evidence have been obtained for the other members analyzed, and the papers are in preparation.(2) Population biology of vatious woodland elements were also studied, using protein polymorphisms (allozyme) as genetic markers. The main emphasis was placed in the genus Fagus, a representative cool-temperate woody group which occurs in several regions in northern hemisphere, including the vast areas in eastem North America (Fagus grandifolia), and in Japan (F.crenata and F.japonica). The demographic genetic structures of 25 local populations at 21 sites of 11 localities in North America were critically examined. Two distinct types, one without root suckers and the other with extensive root sucket formation, are known. Very complex but distinct genetic structures were found to occur in these two types of the North American beech.(3) Demographic genetic structures of typical woodland clonal elements were also studied : Uvularia perfoliata, Disporum smilacinum (both typucal pseudo-annual), and Heloniopsis orientalis. Unexpectedly, much higher genetic variations proved to be pooled at the metapopulation level, with each patch and local population comprising unique genetic variations. Vegetative reproduction is very effective in all these clonal species with regular separation of ramets every season, possibly playing a key role of maintaining such a high genetic variabilities within each metapopulation. Less