Treesearch

The genus Artemisia (Asteraceae, Anthemideae, Artemisiinae) is a large genus, one of the largest genera in its family. It is comprised of about 500 taxa at the specific or subspecific level, distributed in 5 sections or subgenera. Most species are perennial and many are landscape dominants of arid or semiarid regions. Artemisia is widely distributed in the Northern Hemisphere but poorly represented in the Southern Hemisphere. It is more richly represented in Eurasia than it is in North America. A number of Artemisia species have a high economic value for food, medicine, forage, ornamentals,...

Atriplex canescens (Pursh.) Nutt. is the most widespread species of perennial Atriplex in North America, distributed from southern San Luis Potosi, Mexico, to southern Alberta and Saskatchewan, Canada, and from the Pacific Coast of California and Baja California to Texas, Oklahoma, Nebraska, Kansas, and the Dakotas. Throughout its distributional range, A. canescens shows considerable between-population variation. Some of this variation may be due to phenotypic plasticity, but most of it appears to be genetic. Mutations, polyploidy, introgressive hybridization, and segregation from interspec...

Cercocarpus H.B.K. (Rosaceae) taxa are important members of the plant communities of the western states and Mexico, yet the systematics of this genus are unknown primarily from lack of clear morphological delimitations between taxa. In recent years, molecular data have proven useful for resolving relationships among species and the diversity within species that have otherwise remained elusive. We will report here preliminary data on the phylogenetic utility of two noncoding regions within the nuclear ribosomal DNA (nrDNA) for Cercocarpus; the internal transcribed spacer (ITS) region and...

Cheatgrass (Bromus tectorum) individuals were genetically characterized using polymorphic microsatellite markers. Through analysis of alleles of five polymorphic loci, genotypes were constructed of individuals from four populations in Utah and Nevada. There were 15 different genotypes: Whiterocks, UT, had nine genotypes, Hobble Creek, UT, had seven genotypes, Strawberry, UT, had four genotypes and Potosi Pass, NV, had one genotype that was unique among all areas studied. These results are similar to what has been found in previous germination phenology and head smut resistance tests....

Geobotanic research and large-scale mapping with the help of Geographical Information System (GIS) permit us to find out the present state of Kyzylkum Desert shrublands, regularities of plant communities distribution, and chemical composition of the main dominant shrubs. Zonal vegetation types were formed on the basis of Old Xerophilous and Old Mediterranean floras in the Paleogene and Neogene periods. Composition of plant associations and their anthropogenic modification largely depends on physical and chemical properties of the soils. Climax associations of Artemisia diffusa, Astragalus...

Central Asia, and particularly the former Soviet Middle Asian countries, with more than 180 taxa (45 endemics), is one of the centers of origin and speciation of the genus Artemisia L. (Asteraceae, Anthemideae). Several species of this genus, mainly belonging to subgenus Seriphidium (Besser) Rouy, are shrubs that dominate the landscape and form large communities in arid (desertic, semidesertic, steppic, and other) zones of this region. Arid lands constitute approximately 90 percent of the territory of Uzbekistan, and there are approximately 40 Artemisia species. In this paper we present a...

The low stature of ‘Immigrant’ forage kochia (Kochia prostrata) limits its use as winter forage and habitat for livestock and wildlife. In October 1999, a germplasm collection trip was undertaken to obtain forage kochia ecotypes that have potential to improve fall and winter forage. The collection area was north of the Aral Sea in the Clay and Sand Desert Steppes of Kazakhstan. Seed samples brought back to the U.S. included 192 forage kochia ecotypes. The desert shrub ecosystems had major components of chenopods. In general, the area was classified as Brown Desert Steppe, Light Chestnut...

Basin big sagebrush (Artemisia tridentata ssp. tridentata) and mountain big sagebrush (A. t. ssp. vaseyana) hybridize in a narrow zone near Salt Creek, Utah. Reciprocal transplant experiments in this hybrid zone demonstrate that hybrids are more fit than either parental subspecies, but only in the hybrid zone. Do hybrids experience greater, or lesser, use by herbivorous insects, especially in the hybrid zone? And do certain species of herbivorous insects prefer one or the other parental subspecies of big sagebrush? We studied plant-insect interactions in three reciprocal transplant gardens...

In 1866, Gregor Mendel published his experiments on heredity in the garden pea (Pisum sativum). The fundamental principles of inheritance derived from his work apply to nearly all eukaryotic species and are now known as Mendelian principles. Since 1900, Mendel has been recognized as the founder of genetics. In 1900, three botanists, Carl Correns, Hugo De Vries, and Erich Tschermack von Seysenegg, had independently completed experiments that were similar to Mendel’s, although much less extensive. When searching the literature, all three encountered Mendel’s paper and realized that he had...

A primary goal in land management is to sustain the health, diversity, and productivity of the country’s rangelands and shrublands for future generations. This type of sustainable management is to assure the availability and appropriate use of scientific information for decisionmaking. Some of most challenging scientific problems of shrubland ecosystem management are nonnative invasive species, probable effects of global climate change, detrimental effects due to land use change, restoration of degraded environments, and maintaining the quality and quantity of water.