20 



probably follows this vegetative reproduction 

 pattern. 



2. POPULATION SIZE AND CONDITION: Populations in 

 Montana tend to be large; the Little Joe Meadows 

 (002), Pine Creek (006) and Skull Creek (009) 

 populations range from 100 to 1,000 steins counted 

 (ramets) . Even larger populations (greater then 

 2,000 ramets) occur at Skull Creek Meadows (003) 

 and Odell Creek (007) . At least two of these 

 populations (Skull Creek Meadows (003) and Rock 

 Island Lakes (008)) cover approximately five 

 acres. Although populations were large, 

 reproduction was principally vegetative. 



3. REPRODUCTIVE BIOLOGY 



a. TYPE OF REPRODUCTION: Mimulus primuloides 

 reproduces both vegetatively through stolon 

 extension and sexually through production of 

 seed. Although fruiting plants were observed 

 in a number of populations in Montana, 

 reproduction by fruit appears to contribute 

 little to population expansion, since most 

 individuals were observed to have arisen by 

 stolon extension. 



b. POLLINATION BIOLOGY: Not known. 



C. SEED DISPERSAL AND BIOLOGY: A study of 



California populations of M. primuloides at 

 various elevations revealed that mid- 

 elevation populations showed the highest 

 energy allocation to vegetative reproduction. 

 Populations at the highest elevations 

 allocated greater amounts of energy to sexual 

 reproduction (by producing the highest number 

 of inflorescences per individual (stem) ) , but 

 produced the fewest seeds (successful 

 inflorescences) . Observations of natural 

 populations revealed that seedlings were 

 extremely rare in undisturbed populations, 

 and probably contribute only rarely to 

 population increases (Douglas 1981) . 



G. POPULATION ECOLOGY 



1. BIOLOGICAL INTERACTIONS 



a. COMPETITION: Mimulus primuloides occurs in 

 open habitats, and shading may negatively 

 influence plant establishment. From results 



