in.) wide, ^-7 mm. (0.16-0. SB in.) long, obtuse; 

 cauline leaves 3-6, spatulate, cuneate at base, 3- 

 7 mm. (0.12-0. 28 in.) long; inflorescences 3-5 

 flowered, scarcely elongating in fruit; sepals 

 yellowish, oblong, densely pubescent, ^-5 mm. 

 (0.16-0.20 in.) long, 1.5-2 mm. (0.06-0.08 in.) 

 wide, outer pair slightly saccate, inner pair non- 

 saccate; petals yellow, spatulate, retuse or 

 rarely with a deeper sinus at apex, narrowed 

 gradually from blade to claw, 7-8.5 mm. (0.28-0.33 

 in.) long, 3-3.5 mm. (0.12-0.1^ in.) wide; stamens 

 strongly tetradynamous; filaments of paired 

 stamens ca. ^ mm. (0.16 in.) long, anthers ca. 1 

 mm. (0.0^ in.) long; pedicels straight to slightly 

 curved, nearly paralleling rachis, 3-^ mm. (0.12- 

 0.16 in.) high, ^-5 mm. (0.16-0.20 in.) wide, 

 valves densely pubescent on exterior with 

 trichomes that have ascending to erect rays, 

 sparsely pubescent on interior; replum oval to 

 broadly oblong, acute at apex, 2.5-3.5 mm. (0.10- 

 0.1^ in.) long; septum usually folded; styles 2-3 

 mm. (0.08-0.12 in.) long; ovules 2 in each locule; 

 seeds plump, wingless, slightly compressed, 

 orbicular to semiorbicular , ca. 2 mm. (0.08 in.) 

 in diameter; cotyledons accumbent, orbicular or 

 nearly so (Rollins, 198^). 



3. LOCAL FIELD CHARACTERS: During field surveys in 

 1987, one other conspicuous member of the Mustard 

 family, Smelowskia calycina (Alpine Smelowskia), 

 was observed growing with L. humi lis . Smelowskia 

 is distinguished in having white petals, which are 

 sometimes purple-tinged, and plnnatifid or pinnate 

 (lobed or divided) leaves. These are in contrast 

 to the yellow petals and entire (smooth- 

 margined) leaves of L. humi 1 is . Several other 

 species in the Mustard family have been reported 

 from St. Mary Peak, including Arabis spp . and 

 Draba spp. (Lackschewi tz , 1970). Members of 

 Arabis in Montana have white to pink or purple 

 petals and longer, narrow fruits; Draba species 

 often have strongly flattened fruits which are 

 flattened parallel to the septum (internal fruit 

 partition), rather than being not, or only 

 partially, flattened in Lesouerella . 



D. GEOGRAPHICAL DISTRIBUTION 



1. RANGE: Lesguerel la humi 1 is is a state endemic, 

 restricted to three sites in the Bitterroot Range 

 in northwestern Ravalli County, Montana. It is 

 located on the Bitterroot National Forest, in 

 Region 1 (Northern Region) of the U.S. Forest 

 Service. The distribution of the species is 



