0.5-0.7 5 mm wide, narrower than the body; oil tubes 

 prominent, 1 in each interval, 2 on the commissure; 

 carpophore bipartite. 



3. Diagnostic characters: L. attenuatum differs from L. cous 

 which it resembles in habit, leaf dissection, and fruit 

 characters, by having a less conspicuous involucel and greater 

 overall scabrosity (Evert 1983) . 



B. GEOGRAPHIC DISTRIBUTION 



1. Species range: Before its discovery in the Tendoys, the 

 species was known only from Park County in northwestern 

 Wyoming (Evert 1983, Dorn 1992). 



2. Montana distribution: State record (Lesica coll, # 5990) 

 from the Tendoy Mountains, Beaverhead County. 



3. Occurrences in the study area: Two populations were found 

 in the northern Tendoys, one towards the head of Johnson Gulch 

 and another in Limekiln Canyon. Duplicate specimens were 

 verified by a specialist in the Apiaceae, R. L. Hartman (Rocky 

 Mountain Herbarium, University of Wyoming, Laramie) . 



C. HABITAT 



Plants grow in coarse limestone talus or stony soil on warm 

 slopes, usually but not always associated with Cercocarpus 

 ledif alius. Other associates include Agropyron spicatum, 

 Artemisia tridentata, Oryzopsis hymenoides, and Penstemon 

 aridus . 



D. POPULATION BIOLOGY 



The Johnson Gulch population was estimated to consist of over 

 200 plants covering at least 10 acres. The Limekiln Canyon 

 population was estimated at 5,000-10,000+ plants and includes 

 several subpopulations stretching for 2-3 miles in the canyon. 



E. MANAGEMENT CONSIDERATIONS 



L. attenuatum is a narrow endemic listed as 3C by USFWS. At 

 this time it is known from only two sites in Montana. The 

 sites are inaccessible and are not subject to unnatural 

 disturbances. Nonetheless, the rarity of this species makes 

 BLM sensitive species designation appropriate. 



