VEGETATIONAL ANALYSIS OF HABITATS Detailed maps of vegetation within the trapping grid were needed to aid in analyzing distribution of mice within the grid. In preparing such maps, I recorded all plants within a 25 foot radius of each trapping station. The dominant and codominant plants in the overstory (trees or shrubs) were noted at each station. Next the three most abundant plants other than the dominant and codominants were rated for each station, where possible. Finally a listing was made of all remaining species of plants. On the basis of this analysis, four vegetational maps were prepared. One shows associations of dominant overstory and understory plants. Individual maps are devoted to the first, second and third most abundant plants in the ground cover within the trapping grid (Figs. 5-8). Approximately seven man-hours were required to analyze each trapping unit, and 112 man-hours to analyze the entire grid. The home range grid encompasses approximately one million square feet. At least four different vegetational stands occur within the grid: 1) pinyon-juniper woodland with various associations in the understory; 2) _Artemisia tridentata_ (big sagebrush), or _A. nova_ (black sagebrush); 3) _Quercus gambelii_ (Gambel oak); and 4) mixed shrubs--_Fendlera rupicola_ (fendlerbush), _Amelanchier utahensis_ (Utah serviceberry), and _Cercocarpos montanus_ (mountain mahogany). Flora in the ground cover is regulated, at least in part, by the canopy cover; hence different associations of pinyon-juniper woodland and each of the stands mentioned above have different plants, or a different distribution of the same kinds of plants, in their ground cover. Units A, B, E, and parts of D and G in the western third of the grid are in pinyon-juniper woodland (Fig. 5). A relatively pure understory of _Poa fendleriana_ (muttongrass), is typical of such woodland on the middle parts of the mesas. Woodland on the western third of the grid differs somewhat in that, when the area occupied by each plant is considered, _Artemisia tridentata_ is codominant there with _Poa fendleriana_. As far as individual plants are concerned, _Poa_ far outnumbers _Artemisia_. The next most abundant plants in the ground cover are _Solidago petradoria_ (rock goldenrod), _Chrysothamnus depressus_ (dwarf rabbitbrush), and _Penstemon linarioides_ (penstemon), in that order. In unit E there is a large depression, about 200 by 60 feet, created by removal of soil (Fig. 8). _Artemisia nova_ grows there, and pioneering plants adapted to early stages of succession are present.