During the period from October 1950 to March 1951 a study of the taxonomy of the Catostomidae of Utah Lake was undertaken. Throughout this study information was collected on the numbers of suckers taken by some of the fisherman. From the data gathered it appears that the three species of Catostomidae cringinally named from Utah Lake are still there. The external morphological features of these fish are not recognizable unless they are observed very carefully. The most outstanding external characteristics used to differentiate the species are the mouth, lips, papillae on the lips and the general shape of the head. The three species that occur in the lake are Chasmistes liorus, Catostomus fecundus and catostomus ardens. The population counts on these fish showed that the suckers have increased in numbers since the drought of 1934-5 but by no means have reached the point that they held previous to that time. Utah Lake was known during pioneer days as a great sucker pond. The carp, Cyprinus carpio, is the dominant fish in Utah Lake today. This thesis was written in an effort to stabalize the classification of the Catostomidae in Utah Lake, and also to provide data as to the population of the suckers at the present time.

Scorpions from Utah were collected and studied to determine species present, geographic distribution, seasonal occurrence, sex ratio, and some morphological variations associated with distribution. Nine species were identified--Anuroctonus phaeodactylus, Centruroides sculpturatus, Hadrurus arizonensis, H. spadix, Vejovis becki, V. boreus, V. confusus, V. wupatkiensis, and an undescribed species of Vejovis, subgenus Paruroctonus. Five species--C. sculpturatus, H. arizonensis, V. becki, V. confusus, and V. wupatkiensis--are reported from Utah for the first time. Most specimens were collected from May through October, with greatest numbers taken in May, June, and July. Sex ratios differed with the species. Two species--A. phaeodactylus and V. boreus--showed statistically significant morphological variations in the lengths of the preabdomens.

The purpose of this study was to determine the kinds, population, distribution, and general habits of the mammals of the Lynndyl sand dune area. Only one article concerning the dunes was found, but several have been written on other dunes; however, none was found concerning mammals. Two quantitative studies, plot and transect trappings, were made and general observations were taken within the study area. Three types of plots; Russian thistle, juniper, and baren moving dunes; were trapped and revealed the following species: Dipodomys ordii, Peromyscus maniculatus, Reithrodontomys megalotis, Onychomys leucogaster, and Neotoma lepida. The most numerous animal in all plots was Dipodomys ordii followed in all cases by Peromyscus maniculatus. It was found that D. ordii prefer open sand; P. maniculatus, sage and R. megalotis, dense cover. The greatest activity and highest number of catch was in the summer. The major cause for the higher number of catch was the larger number of immature animals cught, but food availability may have had some effect. More than one breeding season, or at least a fluctuatin breeding season, apparently occurs in both predominant species, but further study on this point is recommended. The weights of the specimens were taken. This aided in determining the age of specimens and their breeding activities. Other mammals in the area are: Dipodomys microps, Lepus californicus, Erethizon dorsatum, Odocoileus hemoinus, Taxidea taxus, Vulpes macrotis, and Canis latrans.

How the eggs and larbae of the Utah amphibians differ from each other is the problem to be considered in this paper. Certain problems are yet to be answered. One problem is that the larvae of Rana pretiosa subsp. From utah fit the description of the Nevada form, Rana pretiosa luteiventris, as described by Thompson (1913) and not the description of Rana pretiosa pretiosa as set forth by Svihla (1935). Another problem is that the adults, tadpoles, and eggs of Rana pipiens brachycephala and Rana onca are strikingly similar. Rana fisheri of the Las Vegas Valley in nevada and Rana onca are rather similar. There are fourteen species of utah amphibians. Only twelve of these will be considered here as two species are comparatively rare and material was unobtainable for this study. Variations from previous descriptions of some of the eggs and tadpoles are noted therein. A description of the eggs and tadpoles of Rana onca, Bufo woodhousii microscaphus, Ambystoma tigrinum nebulosum, the eggs of Scaphiopus hammondii intermontanus and the tdpoles of Bufo boreas boreas are advanced for the first time.

The purpose of this study has been to determine : (1) the mammalian species present in the Mud Creek area; (2) the approximate population density of each trappable species; (3) the species responsible for the damage; (4) the stem density and frequency of Smbucus racemosa; and (5) the approximate extent of damage to the red elderberry stems.

The Weberian mechanisms of three Utah Lake suckers (Catostomidae: Catostominae; Catostomini), Catostomus fecundus Cope and Yarrow, Chasmistes liorus Jordan, and Catostomus ardens Jordan and Gilbert, were examined, described, and compared, and a statistical analysis was made of some of their more important differences. The mechanisms were found to be basically similar to one another and to those of other Catostomini as previously described and/or illustrated. They are individually distinct, but each varies within its own limits, the intraspecific variation being greatest in the wider-ranging Catostomus ardens and least in the seemingly most restricted Catostomus fecundus. From the evidence at hand it appears that the above taxa are three distinct species. Chasmistes liorus is more abundant that Catostomus fecundus; Catostomus ardens presumably is very rare. Catostomus fecundus seems more closely related to Chasmistes liorus, and future studies may verify that Catostomus fecundus should be transferred to the genus Chasmistes.

This study is a taxonomic revision of the genus Ranunculus for Utah. Twenty-five species and 4 varieties are recognized, and are separated by means of a comprehensive key. A list of pertinent synonyms and types, a morphological description, habitat preference and a discussion are presented for each species and variety. Distribution maps and photographs are included. The basis of this study has been morphological comparison of herbarium specimens and collections and observations by the author throughout Utah.

Within the genus Cercocarpus H.B.K., commonly called mountain mahogany, there are three species, C. monanus Raf., C. ledifolius Nutt., and C. intricatus S. Wats., that occupy rather distinct habitats in Utah. During the past two years a study of Cercocarpus populations growing throughout Utah has shown not only that hybridization does occur between all three species but that in some instances viable progeny are produced from these F1 hybrids. Despite rather severe isolation barriers, there is sufficient plasticity to permit inter-breeding under certain circumstances.

The taxonomy and distribution of the Astragalus lentiginosus complex in Utah is presented. The nine varieties are listed and a key is provided which allows determination of the members of the complex in Utah. Each entity is discussed and illustrated. Two distribtuion maps are included for each variety, one showing the distribution in Utah and the other, the general range of the entity. The body of this work is based on the study of herbarium specimens and field observations and collection. These studies have resulted in the synonymizing of two varieties, the inclusion of another and one nomenclatural change.

The ecological life history of budsage (Artemisia spinescens D.C. Eaton) was investigated during 1963 and 1964. The field studies were conducted at the Desert Experimental Range in Millard County, Utah. Laboratory studies were done at Brigham Young University. The different community types in which budsage grows were described and the physical site factors, viz. climate, soil texture, total soluble salts, hydrogen ion concentration of the soil, carbonate content and soil moisture were investigated. Phenology of seedlings, root systems, shoot and flower development, and plant longevity were investigated. Studies were also made on the effects of different seasons and intensities of grazing as they affect flowering, herbage yield, number of plants present and longevity. The various communities studied in which budsage grows were classed into three kinds, viz. budsage-winterfat types, shadscale types including winterfat, and shadscale types without winterfat. The budsage-winterfat types grow in soils which have markedly less gravel between 20 to 30 inches deep than the soils of the other communities studied. The moisture holding capacity of these soils is less than 10 percent in the first two feet. The soils which support shadscale types containing winterfat have less gravel in the upper horizons than the soils which support budsage-winterfat types. The moisture holding capacity of these soils is greater than 10 percent in the upper horizons and are more saline and shallower than the soils which support budsage-winterfat communities. The shadscale types without winterfat are located in the valley bottoms , grow in deep soils which have little gravel and have no salt accumulation in the first 2 feet. Establishment of bud sage seedlings require moist soil for at least one month before drought conditions occur. The seedlings have a taproot, but as the plant matures it becomes a highly branched, shallow root system, which is usually well distributed in the surface layers of the soil. This kind of a root system is probably its principal adaptative characteristic for drought conditions. Budsage ordinarily begins growth in early spring, but in 1963 and 1965 it broke dormancy in response to late summer storms in August. Both these years it was usuable sheep forage throughout the entire grazing season. Budsage completed growth by the first of June, lost its leaves and flower heads in late June and become dormant in early July in both 1963 and 1964. Survival of individual budsage plants was better under mid winter grazing than under late winter grazing. Late winter grazing regardless of intensity allowed very few budsage plants to become established. The season of grazing was more important than intensity of grazing in causing changes in the cover and number of plants. Late winter grazing decreased both the amount and number of budsage. However grazing in this season was most detrimental what it was at a heavy intensity.