Not until 1933 did the classification of Amador's flowering plants appeal to him as a project for future study. In that year, he had his first class in Taxonomic Botany at the University of California. Collecting hin this territory was a definite advantage to him as his acquaintance with the land owners enabled him to trespass and collect without question. HIs acquaintance with the territory also made it possible for him to know where many specimens of infrequent occurrence were to be found. Had he been unfamiliar with the territory certainly many of these would have been missed. This thesis represents the fulfillment of an idea almost ten years old. Its completion is largely a result of the timely counsel, inspiration and encouragement extended by Dr. E. E. Stanford, Professor of Botany at the College of the Pacific. The specimens collected have been contributed to the College of the Pacific Herbarium, of which it forms a permanent part. It is his hope that this collection may be of value to the college. STATEMENT OF PROBLEM The purpose of this study was to collect and classify all the flowering plants, grasses excluded, that occur in the Plymouth-Bridgeport Area of Amador and El Dorado Counties, California. Data are presented as to location, habitat, elevation, collection date, and economic importance because of use by the populace of that area. TERRITORY The territory covered extends from the Amador-Sacramento County line at an elevation of 220 feet to a point fifteen miles east of Plymouth at an elevation of 3000 feet. Collections were made in both Amador and El Dorado Counties. Trips extended up the Cosumne River, boundary line of Amador and El Dorado Counties, covering adjoining territory to a distance of five miles north and south of the river. Hence, the territory covered in this study includes a strip of land ten miles wide and thirty miles long, the Cosumne River running from east to west down through the center of the area. COLLECTION DATES Collection dates extended February to July, 1942. The author covered the territory at frequent intervals in an effort to make the specimen collection as complete as possible. LIFE ZONES The Life-Zones covered in this study includes the Valley Sonoran, Upper Sonoran, and Sierra Transitions. These will be discussed in the order mentioned. REFERENCE In this study the key to plant families was adapted from Willis Linn Jepson's Manuel of the Flowering Plants of California. (Hereafter referred to as Jepson.) This reference was used for the classification of all specimens collected in this study. SPECIMEN ARRANGEMENT In this study the families and genera and species within the families were arranged alphabetically rather than according to Jepson. This was done for convenience in working with and referring to the specimens collected.