XX Journal of Agricultural Research voi.xvni 



Determination of Normai, Temperatures by Means of the Equation 

 OP THE vSeasonal Temperature Variation and a Modified Thermo- 

 graph Record 



Page 

 Fig. I. Synoptic chart of annual temperature marches at selected stations in 



the United States 501 



2. Mean monthly temijeratures for Utah 502 



3. Average Utah thermograph records for various seasons 504 



4. Actual thermograph records taken at widely separated stations in the 



United States 505 



5. Hourly variation of tempe;:atures expressed in percentages of the mean . 507 



6. Effect of storm on diurnal variation of temperature 509 



Temperature Relations of Certain Potato-Rot and Wii,t-Producing 



Fungi 



Fig. I. Graph sho^^ ing the rate of growth of Fusarivm coeruleum on potato agai 



at different temperatures 513 



2. Graph showing the rate of growlh of Fusariuni discolor var. sulphureum 



on potato agar at different tem^peratures 514 



3. Graph showing the rate of gro\\th of Fusariuni eumartii on potato agar 



at different ten^peratures 515 



4. Graph showing the rate of gtowlh of Fusariuni oxysporum on potato 



agar at different temperatures 516 



5. Graph showing the rate of growth of Fusariuni radicicohi on potato agai 



at different temperatures 517 



6. Graph showing the rate of growth of Fusariuni trichothccioiies on potato 



agar at different temperatures 518 



7. Graph showing the rate of growth of VcrtirJlUum albo-atruvi No. 426 on 



potato agar at different temperatures 519 



8. Graph showing the rate of growth of Vcriicillium alho-nirum No. 427 on 



potato agar at different temperatures 519 



9. Graph showing the total amounts of gro^nh produced by different 



potato-rot and wilt-fungi during the first seven days on potato agar 



at different temperatures 520 



Germination op P>arley Pollen 



Fig. I. Period of receptivity of the stigma under .field conditions as shown by 

 the number of seed produced when 40 flowers w^ere pollinated on 

 emasculation and the same number on six successive days after 



emasculation 528 



2. Number and percentage of seed produced by the use of pollen from 



anthers at various stages of de velopment before and after dehiscence . . 529 



Effect of the Relative Length of Day and Night and Other 

 Factors of the Environment on Growth AxNd Reproduction in 

 Plants 



Fig. 1 . Graph showing the shortening of the vegetative period preceding flower- 

 ing soybeans which results from progressively later planting during 

 the growing season 568 



2. Graph showing changes in length of day during the growing season in 



the latitude of Washington, D. C 569 



3. Graph showing the progrcssi\e decrease in height attained by Biloxi 



soybeans as the date of planting is delayed beyond late spring 570 



