feet at Holter Dam) . For the period of 1951-1980, 

 the mean annual precipitation at Holter Dam was 

 12.02 inches, the mean January temperature was 

 24.8°F, and the mean July temperature was 69.9°F 

 (U.S. Department of Commerce 1982.) 



POPULATION DEMOGRAPHY, BIOLOGY AND SPECIATION 



1. PHENOLOGY: Astragalus convallarius var. 



convallarius flowers in May and June, continuing 

 through to August under favorable conditions. 



2. POPULATION SIZE AND CONDITION: Astragalus 



convallarius var. convallarius is reported as 

 being "common and locally abundant" in its range 

 outside Montana (Barneby 1964) . In Montana 

 species frequency is recorded as "abundant" or 

 "locally common" in its Beaverhead County sites 

 and at least one of its Broadwater County sites. 

 Small, widely-scatter populations or sub- 

 populations are documented below the Helena 

 National Forest Service boundary in the Elkhorn 

 Mountains, as well as above Helena. The Helena 

 National Forest population is described as having 

 less than 10 individuals; however, the population 

 may be larger as the plant is difficult to see, 

 the weather was dry, and the search time was 

 short. 



3. REPRODUCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: Assumed to be sexual. 



b. POLLINATION BIOLOGY: Assumed to be insect- 



pollinated. 



c. SEED DISPERSAL AND BIOLOGY: Although the pod 



of Astragalus convallarius var. convallarius 

 probably splits rapidly from tip to base, the 

 force of the release is seldom so violent as 

 to eject the seeds any great distance 

 (Barneby 1964) . Nothing else is known 

 concerning the seed dispersal or seed biology 

 of this taxon. 



d. PHYLOGENY AND SPECIATION: Although Barneby 



discusses the phylogeny of Astragalus at some 

 length (see Barneby 1964, pp. 20-31), he does 

 not provide a comprehensive phylogenetic 

 system. Also A. convallarius var. 

 convallarius is not specifically mentioned in 

 the text. 



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