3. SOIL RELATIONSHIPS: All of the Beaverhead County sites are on 

 gravelly calcareous mollisols derived from Madison Group 

 limestone. Even though the Sweetgrass Hills has limestone 

 outcrops, both sites of the Halimolobos virqata are on sandy 

 mollisols derived from the Eagle Sandstone Formation. 



4. REGIONAL CLIMATE: The foothills settings occupied by Halimolobos 

 virqata have climatic conditions most resembling those monitored 

 nearby in Chester, MT. It is the climate of semi-arid steppe, 

 including low precipitation, cold winter, s and hot summers. 



F. POPULATION DEMOGRAPHY AND BIOLOGY 



1. PHENOLOGY: Plant collection dates in Montana range from May 28 - 

 July 13, but all five of the specimens were collected when 

 primarily or totally in fruiting condition. It is extrapolated 

 that flowering begins by early May, and may be prolonged into 

 early summer by indeterminate growth and branching off the main 

 stems under favorable conditions, with flowering and fruiting 

 overlapping for at least a couple weeks. It is more conspicuous 

 in flowering than fruiting condition. Fruits are needed for 

 positive identification. 



2. POPULATION SIZE AND CONDITION: The total number of plants in the 

 state represented by known populations is between 500-1100 

 plants, based on population estimates at the five known sites. 



EG no. Population size 



001 Sweetgrass Hills - Dohrs Creek; highly discontinuous 

 along two-track road totalling 50-100 plants 



002 Sweetgrass Hills - Sage Creek; one population center of 

 200-300 plants 



003 Tendoy Mts. - Pileup Canyon; one population center of 

 ca. 100 plants 



004 Tendoy Mts. - Limekiln Canyon; one population center of 

 100-500 plants 



005 East Pioneer Mts., uncommon in one population center 



3. REPRODUCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: Halimolobos virqata reproduces from seed 

 only. Most biennials do not produce seed until their second 

 year. In the Sweetgrass Hills, most Halimolobos virqata plants 

 were the same height (ca. 2 dm) , but stunted plants were also 

 seen - it is possible that the less vigorous plants are ones 

 which produced seed in their first year rather than just 

 producing rosettes. Rosettes of Halimolobos virqata were not 

 found in close inspection around flowering plants, but may have 

 been overlooked. 



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