densely pubescent, 6-7 mm. long, ca. 2 mm. wide; 

 petals white to purplish, obovate, not 

 unguiculate, narrowing gradually from blade to 

 point of insertion, 9-13 mm. long, 3-5 mm. wide ; 

 fruiting pedicels erect to slightly divaricately 

 ascending, straight, 6-10 mm. long; siliques 

 erect, congested, usually appressed to rachis, 

 straight to slightly curved inward, 3-5 cm. long, 

 ca. 1.5 mm. wide, valves densely pubescent, 

 compressed between seeds; styles ca . 1 mm. long; 

 seeds in a single row, suborbicular to slightly 

 longer than broad, narrowly wing-margined all 

 around, ca. 1.2 mm. in diameter, mucilaginous when 

 wetted; cotyledons accumbent (adapted from Rollins 

 1984) . 



3. LOCAL FIELD CHARACTERS: The very erect fruits, 



and the dense greyish vestiture of branched hairs 

 on the foliage and fruit, distinguish A. fecunda 

 from all other Arabis species found in western 

 Montana (Lesica 1985) . 



GEOGRAPHICAL DISTRIBUTION 



1. RANGE: All 13 of the currently known populations 

 of A. fecunda occur in southwestern Montana. 

 There are four locations for A. fecunda along the 

 western flanks of the Sapphire Mountains east of 

 Hamilton, Ravalli County, Montana. Nine 

 additional locations were recently documented (8 

 in 1988, 1 in 1989) from small drainages on the 

 north and east flanks of the East Pioneer 

 Mountains: Jerry Creek, Quartz Hill Gulch, Canyon 

 Creek, Cattle Gulch, and Birch Creek. 



The global distribution for this species is shown 

 on Map 1, p. 4. The exact locations are shown on 

 the maps in Section IV, pp. 31-38. The 

 populations occur in Beaverhead (7), Ravalli (4), 

 and Silver Bow (2) counties, Montana. 



2. CURRENT SITES: In 1988 and 1989, field surveys of 

 southwestern Montana revealed nine new populations 

 of A. fecunda . This brings the total number of 

 currently documented populations to 13. Five of 

 the populations occur on lands that are partially 

 or wholly privately owned, six are on lands 

 managed by the U.S. Forest Service, and three are 

 partially or wholly on lands managed by the Bureau 

 of Land Management and/or State of Montana. The 

 legal descriptions, elevations, USGS topographic 

 map names, and locations of sites in Montana are 



