Physiognomy and Structure: The shrublands in this alliance are characterized by an open to dense (10-75%) cover of microphyllous evergreen shrubs, usually 1-2 m in height. Cespitose graminoids are scattered in the shrub matrix and can occasionally match the shrubs in height. A sparse, emergent layer of scale-leaved or needle-leaved evergreen trees may also be present, but in many areas no trees are present. Forb species may be frequent, but are usually of low cover. With increasing summer rain in the southeastern edge of the range, there is an increase in the importance of sod-forming grasses in comparison to bunchgrasses. In many areas, undisturbed stands in this alliance will have a cryptogamic soil crust composed of a mix of lichens, tiny mosses, and bacteria.

Floristics: The vegetation included in this alliance is characterized by an open to dense (10-70% cover) short-shrub layer in which Artemisia tridentata ssp. vaseyana is codominant, usually with 40-60% relative cover, with non-sagebrush shrub species such as Amelanchier utahensis, Holodiscus dumosus, Purshia tridentata, or Symphoricarpos oreophilus. Perennial graminoids typically dominate the open to moderately dense herbaceous layer. The most widespread species are Pseudoroegneria spicata and Festuca idahoensis, which occur from the Great Basin to the Rocky Mountains, although they may not be the most abundant species in individual stands. Other locally important species may include Bromus carinatus, Elymus trachycaulus, Hesperostipa comata, Koeleria macrantha, Muhlenbergia montana, Poa fendleriana, and Poa secunda. The forb layer is variable and can be very diverse. Species of Castilleja, Potentilla, Erigeron, Phlox, Astragalus, Geum, Lupinus, and Eriogonum are characteristic.

Dynamics:  Complex ecological interactions between fire regimes, grazing history, and climate patterns result in equally complex patterns of species structure and composition in Artemisia tridentata. These present corresponding difficulties in the classification of these shrublands, which have been compounded by the influence of human settlement and agricultural patterns. What follows is a summary of some of the influences of altered fire regimes, and grazing history on Artemisia tridentata shrublands and shrub herbaceous vegetation.

Artemisia tridentata ssp. vaseyana shrublands may represent either drier or more disturbed examples of the Artemisia tridentata ssp. vaseyana shrubland complex. Shrub densities typically increase with overgrazing of the bunchgrass component or with increasing summer drought (West 1983c). There is considerable debate over whether present shrub-dominated stands are actually degraded "steppe" (e.g., shrub-herbaceous physiognomy), and if the stands will return to steppe with changes in grazing and fire management. Artemisia tridentata is inhibited by fire, and excessive grazing may decrease fire frequency due to consumption of herbaceous forage, resulting in increased shrub density. Conversely, invasion by non-native annual grasses (e.g., Bromus tectorum at lower elevations) may increase fire frequency sufficiently to eliminate the shrubs from the stands (Hironaka et al. 1983). With a change in fire frequency, species composition will be altered as well (West 1983c). With a high fire frequency (every 2-5 years), perennial grasses and shrubs are eliminated and non-native annual grasses dominate. At fire-return intervals of 10-30 years, short-lived resprouting shrubs such as Chrysothamnus or Tetradymia spp. dominate. At fire intervals of 30-70 years, a mixture of perennial bunchgrasses and shrubs is maintained. Finally, in the complete absence of fire, deep-rooted shrubs such as Artemisia tridentata become the theoretical dominants.