53 



3. Physiographic province: Within the Northern 

 Rocky Mountain Province mapped by Fenneman 

 (1931); within the Rocky Mountain System, 

 Rocky Mountains in Montana and Canada 

 Province, mapped by Hunt (1974). 



Physiographic and topographic 

 characteristics: Grindelia howel 1 ii occurs 



in association with two geo 1 

 in Montana. In the lower el 

 in the vicinities of Ovando 

 Junction, it occurs on Terti 

 the Willow Creek formation; 

 comprised of glacial deposit 

 deposited in the Cenozoic Er 

 adjacent low mountains, it o 

 of much older sedimentary ro 

 the Upper Belt formations of 

 Missoula groups; these forma 

 Precambrian in age, and cons 

 and argillite (Perry, 1962). 



ogic formations 

 evation valleys 

 and Clearwater 

 ary sediments of 

 these are 

 s and al luv i urn , 

 a . In the 

 ccurs in areas 

 ck, comprised of 



the Piegan and 

 t ions are late 

 ist of quartzi te 



Known sites occur at elevations of 2500 feet 

 in Idaho to 4B80 feet in Montana. All known 

 populations occur in level to gently sloping 

 areas; no sites were found on steep slopes. 

 In several locations associated with largely 

 undisturbed habitat (i.e., Holland Lake 

 (001), Cottonwood Creek (040)), the species 

 occurs abundantly in slightly concave areas, 

 suggesting that it naturally prefers somewhat 

 mo i ster si tes . 



In Montana, the species occurs in the Swan 

 and C learwa ter /B 1 ackf oo t River drainages. 

 These areas are within Hydrologic Unit Nos. 

 17010211 and 17010203, respectively, as 

 mapped by the United States Geological 

 Survey ( 1980) . 



5. Edaphic factors: Most sites occur on 



gravelly loam or loam soils; at a few sites, 

 soils are of a clay loam or silt loam 

 texture. Gr i ndel i a howel 1 i i occurs 

 frequently in disturbed areas. These sites 

 are found along the shoulders of gravel 

 roads and old logging trails where soil 

 compaction appears greater, and moisture 

 retention is presumably higher. These 

 observations, plus the occurrence of numerou; 

 plants in slight depressions at several 

 undisturbed sites, suggest that G. howe 1 1 i i 

 prefers soils which are slightly to poorly 

 dra i ned . 



