A FLORISTIC SURVEY OF THE BEAR TRAP CANYON, MADISON COUNTY, MONTANA, WITH A DISCUSSION OF AUTHOR CITATIONS USING THE CONNECTING WORDS IN OR EX Porter P. Lowry II Department of Botany University of Illinois Urbana, IL 61801 ABSTRACT: The results of a floristic survey of the Bear Trap Canyon are presented in the form of an annotated checklist. Two hundred and forty-two taxa are listed representin.s 162 genera and 50 families. Habitat and distributional data are provided for each taxon. The checklist is prefaced by a discussion of the topography and major plant community types of the area. Problems concerning author citations using the connecting words in or ex, and the consequences of their incorrect usage, are discussed. A floristic survey of the Bear Trap Canyon, Madison County, Montana, was conducted during the summer of 1979 while the author was employed by the Butte District Office, Bureau of Land Management, U.S. D.I. The study was made in order to determine the total vascular plant flora of the area, as well as to assess the occurrence, frequency, and distribution of actually or potentially threatened or endangered plant taxa, in compliance with the Endangered Species Act of 1973 (Public Law 93-205) . The Bear Trap Canyon, also known locally as the Madison Canyon, is located on the Madison River 13 km by air (17 km by road) NNE of Ennis, MT, in an area where the river cuts through the Precambrian bedrock of the Norris Hills (de la Montagne, 1960). Here the river flows rapidly to the north, dropping from an elevation of 1470 m at Ennis Lake to approximately 1420 m at the Missouri Flats located at the north end of the canyon. Throughout much of its nearly 16 km length this sharply incised, V-shaped canyon is in excess of 400 m deep. A small dam, associated with the Madison Powerhouse, is situated about 3.5 km N of the entrance to the canyon, and a primitive settlement has been established at the confluence of Bear Trap Creek and the Madison River. An undeveloped trail runs along the E bank of the river. The vegetation differs drastically between the E and W sides of Bear Trap Canyon. In general, the eastern slope (W-facing) has large stands of rich, fairly mesic forest dominated by Pseudotsuga menziesii var. glauca , which often extend down to the shores of the Madison River. Individuals of Pinus contorta var. latifolia occur in drier areas. A large number of herbaceous taxa is found in these forests, including Osmorhiza chilensis , Arnica cordifolia var. cordifolia , Mertensia oblongifolia var. oblongifolia , 81
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