ECOLOGY. 395 



coming evident that the response of a species of bee is largely deter- 

 mined by the grouping of the flowers in the different types of in- 

 florescence. 



The further results of competitive studies confirm the conclusion 

 that each species of pollinator has a preferred flower, which it visits 

 almost exclusively during its prime. At this time the great majority 

 of individuals can not be attracted to other flowers, no matter what 

 their proximity, but a few will occasionally visit competition clusters. 



Experiynental Taxonomy, by F. E. Clements and H. M. Hall. 



During the summer of 1921, attention has been given chiefly to 

 following the development of transplants already made, though a num- 

 ber of alpine and plains species have been moved into the montane 

 gardens. All previous transplants have received attention, and rec- 

 ords have been made as to the conditions of growth, changes due to the 

 environment, etc. Approximately 925 perennial transplants, repre- 

 sentmg 325 species and varieties, are now growing in their new habi- 

 tats. A few of these were moved in 1918, but most of them have been 

 established for only 2 years. More than 50 per cent of the plants 

 taken from the plains to the alpine region liave died. The remainder 

 are living, but apparently the season is too short for the production of 

 flowers and seed, or even for the development of normal foliage. Those 

 that have made the best growth under the rigorous conditions are spe- 

 cies of Stipa, Monarda, and Artemisia. 



Of 100 species transferred from above timber-line (12,000 feet) to 

 the gardens at Minnehaha (8,200 feet) but G have been entirely lost. 

 This small loss is partly due to the precaution of placing every species 

 in two or more unlike situations. The total number of plants moved 

 from the alpine region to the montane gardens is 200, of which 48 have 

 died. Some of those living are quite small, others are more robust 

 than the normal alpine individuals, and 39, representing 33 species, 

 have set flowers. It is highly desirable that a considerable quantity 

 of each alpine species be grown at the lower altitudes to furnish material 

 for experimental and statistical studies. With this in view a begin- 

 ning has been made in transferring certain species in large quantities. 



While it is yet too early to expect considerable changes in most of 

 the transplants, some of them have already undergone extensive modifi- 

 cation. The application of these methods to taxonomy is illustrated 

 by the use made of results obtained from forms of Artemisia vulgaris. 

 This polymorphic species is represented in the vicinity of the Colorado 

 transplant stations by two distinct varieties commonly accepted as 

 species. These are ludoviciana, in which the leaves are only sparsely 

 pubescent above, and gnaphalodes, which has the foliage densely 

 white-tomentose on both sides. These two forms were used to make a 

 series of reciprocal transplants. After 3 years it was found that plants 



