82 REIPORTS OF INVESTIGATIONS AND PROJECTS. 



A Study of Selective and Environmental Factors. — E. N. Transeau. 



During the absence of Dr. Shull I continued his experiments on the forms 

 of Bursa hursa-pastoris, and studied critically several thousand plants, repre- 

 senting most of the families grown during the past year. 



Of the 53 normal and abnormal plants of Trillinni grandifloritm trans- 

 planted to the garden in the spring of 1906, 38 survive. Of the 15 plants 

 which did not develop stem and leaves this year, 14 were of the abnormal 

 type and included all of the extreme forms. The plants were somewhat 

 reduced in size and all of the abnormal plants again failed to produce seed. 



Considerable attention was paid to the leaf variations of Rumex acetosella. 

 Forms having leaves with from i to 5 extra lobes were found in the vicinity 

 of the laboratory and grown along with normal and lobeless forms. Guarded 

 crosses were made among all of the forms and an abundance of seed secured. 

 This plant was also used in a series of cultures to show the progressive 

 effects of soil conditions on leaf size and form. Three very different soils 

 were used and guarded seeds collected from each soil. 



An attempt is being made to determine the chances of survival of single 

 mutants of Oenothera lamarckiana growing in the midst of the parent species. 

 About 2,000 seedlings, representing the progeny of the mutant and its 

 neighboring plants, have been recorded. 



Four species of Lepidium, represented by 2,672 plants, were grown for 

 observation of variations and hybridization. All crosses thus far made failed 

 to produce fertile seed. 



Eight species of Ipomoea, represented by 200 plants, were grown in the 

 garden. From these a large collection of self-fertilized seed has been ob- 

 tained. 



Work on the natural distribution of the vegetation about Cold Spring 

 Harbor has been continued throughout the year. A report on this work will 

 be made shortly. The transpiration conditions in most of the habitats have 

 been studied by means of evaporimeters. Comparative results have been 

 obtained by use of a standard instrument placed in the garden. This latter 

 instrument was standardized to the evaporimeter of the Desert Botanical 

 Laboratory, so that all of my readings are directly comparable with those at 

 the latter station. The results indicate remarkable dift'erences in the moisture 

 conditions in the several habitats. A report on these evaporation records is 

 in course of preparation. 



Since coming to Charleston, Illinois, arrangements have been completed 

 whereby greenhouse and garden space have been provided for the continu- 

 ance of the breeding work with Rumex and Ipouuva. 



RESIDENT STAFF. 



The staff remains the same as last year, except that Prof. E. N. Transeau, 

 who came to us from Alma College, Michigan, in July, 1906, has accepted 

 a call to the Illinois State Normal School, Charleston, Illinois, as professor 

 of botany. Dr. Transeau brought to the work the training of a plant physiol- 

 ogist and ecologist, a training that tended to broaden the work of the Station. 

 Fortunately he will be able to continue as associate of the Station some of 

 the investigations started here. 



The vacancy made by the resignation of Dr. Transeau has been filled by 

 the appointment of Dr. J. Arthur Harris as botanical investigator. Dr. 



