20 



of relatively erosion resistant limestone (Heidel 1993). 

 The elevation of these sites ranges from 5,600 to 7,440 

 feet. The Rocky Hills site is an upper slope with southwest 

 aspect at around 7,200 feet. 



3. Soil relations: The soils of most Beaverhead County sites 

 are derived from calcareous formations of the Madison Group, 

 but the high elevation site in the Centennials has soil 

 derived from quartzite (Heidel 1993). The population 

 locations and boundaries in general seem strongly controlled 

 by edaphic substrate; the Centennial Mountain occurrence is 

 an anomaly which deserves further evaluation. The soil at 

 the Rocky Hills site is a shallow, gravelly clay derived 

 from loose limestone scree, and was dry by the survey date 

 (June 29) . 



E. Population demography and biology 



1. Demographic details: Numerical estimates of population size 

 range from 50 to thousands of plants, and the taxon was 

 considered "common" at two recently surveyed sites. 

 Populations with lower estimates have not been completely 

 surveyed, and may be underestimated; when the population 

 near Bannack was originally discovered only 9 plants were 

 found (Heidel 1993), but over 1,000 plants were estimated in 

 1994 (Vanderhorst 1995b). The population in the Rocky Hills 

 was estimated to consist of between 1,000 and 10,000 plants 

 and to cover 15 acres. 



2. Reproductive biology: Lesquerella sp. novum I is a small, 

 probably short-lived perennial which reproduces entirely by 

 seed. Species of Lesquerella are generally cross-pollinated 

 and self-incompatible (Rollins and Shaw 1973). The plants 

 generally flower from late May to late June, with flower and 

 fruit stages often overlapping on the same plant and within 

 an inflorescence due to indeterminate growth habit (Heidel 

 1993). Flowering was completed and seed were dispersing at 

 the survey date (June 29) of the Rocky Hills population. 



The population structure, habitat, and plant habit of 

 Lesquerella sp. novum appear to be very similar to those of 

 Lesquerella carinata var. lanquida , whose population biology 

 has been studied in depth (Greenlee 1994). These 

 bladderpods seem to have populations which are subject to 

 large fluctuations in numbers which follow climatic cycles, 

 especially at severe (i.e. hot, dry) sites. 



E. Management considerations: 



The population of Lesquerella sp. novum I in the Rocky Hills is 

 in near-pristine habitat which is not threatened by current land 

 uses. Cattle grazing is concentrated on lower, less steep 

 terrain with more productive vegetation types, and the 



