Sequence data of the chloroplast gene rbcL were used to estimate the time of the well-known eastern Asian-eastern North American floristic disjunction. Sequence divergence of rbcL was examined for 22 species of 11 genera (Campsis, Caulophyllum, Cornus, Decumaria, Liriodendron, Menispermum, Mitchella, Pachysandra, Penthorum, Podophyllum, and Phryma) representing a diverse array of flowering plan...

A simple evaluation of the phase change in a diffracted wave, in terms of the Cornu spiral, is presented to complement the well-known intensity change, which is routinely obtained for this elegant graphical construction of the Fresnel integrals. This is, to the best of our knowledge, the first presentation of this evaluation. It is shown that the phase of a wave diffracted by a slit is equal to...

The relationship of freezing resistance to water permeability of cortex cells was studied in stems of red osier dogwood (Cornus stolonifera Michx.). Permeability was estimated by determining the diffusion flux of tritiated water from cortex slices previously equilibrated in tritiated water. Energy of activation and diffusion time comparisons of tritiated water flux from living cortex slices and...

Data from four DNA regions (rbcL, matK, 26S rDNA, and ITS) as well as extant and fossil morphology were used to reconstruct the phylogeny and biogeographic history of an intercontinentally disjunct plant group, the cornelian cherries of Cornus (dogwoods). The study tests previous hypotheses on the relative roles of two Tertiary land bridges, the North Atlantic land bridge (NALB) and the Bering ...

Cornus macrophylla is important traditional and endangered plant species of western Himalaya. In Pakistan it is found in Nandiar and Hillian sub-valleys of district Battagram in range of 1800-3000 m. It is also present in China, Japan, Afghanistan, and India from 1500-2700 m. C. macrophylla stem bark contains flavonoide ontents. According to the International Union for Conservation of Nature (I...

Global climate change and increased land use lead to the loss of biodiversity at all levels organization living organisms – ecosystems, species, landscape population, genetic, molecular biological levels, etc. The reaction plants anthropogenic impact, according experts, may be even stronger than postglacial changes. A shift in thermal isotherm will cause either move adapt, or disappear. Endemic...