are more or less obviously related to the climatic regime in which 

 various natural populations of the plants grow. One question the 

 Carnegie group asked is whether or not these local differences in 

 plant "behavior" have a genetic basis or merely represent a plas- 

 tic response to the ecological differences among the various 

 habitats occupied by Achillea. A second question was whether 

 or not the plants from various localities would be able to tolerate 

 environmental conditions outside their locality of origin, and if 

 so, to what extent they were tolerant of these conditions. The 

 stem length and stem number that I have chosen to list in the 

 table above may be taken as a measure of the general vigor of 

 plants in the various transplant localities. The time of flowering 

 may provide some basis for estimating whether or not a plant 

 that is able to thrive vegetatively in an area can actually reproduce 

 in the area via seeds. 



The figures given in the preceding table provide some interest- 

 ing insights into the genetic and ecological nature of Achillea. 

 The Bodega population obviously does best at Stanford in view 

 of its stem characters there, although it also does relatively well 

 at Mather. However, the plants of this population flower at 

 Mather in July whereas at Stanford they flower in May. No Bod- 

 ega plants survived at Timberline. The response of the Clayton 

 population was similar to that of the Bodega population. How- 

 ever, the Clayton population is taller than the Bodega population 

 at both Stanford and Mather, indicating that there are some 

 genetic differences that affect plant height between the Clayton 

 and Bodega plants. The two races are also different in flowering 

 time. The Mather population does best at Mather, which is no 

 surprise. It also produces tall stems at Stanford, although the 

 number of stems is reduced. There is also a six week difference 

 in flowering time in the two gardens. Mather plants can survive 

 at Timberline and can even flower there; however, because they 

 flower in late September, it is doubtful whether the Mather plants 

 could reproduce successfully at Timberline, since maturation of 

 seed would be stopped by the first killing frosts. The Big Horn 

 Lake population can survive and flower at all three sites. The 

 plant height and vigor are best at Timberline, however, suggesting 

 that for all the rigors of the alpine climate, the Big Horn Lake 



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