1919] FIELD CROPS. 441 



time of blooming of several varieties of wheat and on the fertilization of emas- 

 culated wheat flowers left unprotected from foreign pollination. 



Different types of wheat, represented by Velvet Chaff, Haynes Bluestem, 

 Glyndon Fife, Kubanlva, Arnautka, Kharkov, and Turkey at St. Paul, and by 

 Dietz, Fultz, Mealy, Giant Squarehead, Turkey, Bluestem, and Fife at Arlington, 

 were examined for time of blooming. Individual heads were marked and a 

 diagram prepared upon which the flowers were recorded as they bloomed. Ex- 

 aminations were made usually at 7 a. m., 12 m., and 5 or 6 p. m. A flower was 

 considered as liaving bloomed when the glumes Imd opened appreciably. It is 

 stated that " the process of blooming of a wheat flower is very rapid. From the 

 time that they first begin to open the glumes may be fully open in less than 1 

 minute ; the anthers may be extruded and emptied of pollen within 2 or 3 

 minutes ; the glumes may be half closed within 5 minutes, loosely closed within 

 10 minutes, and tightly closed at the end of 15 or 20 minutes. The entire 

 process, from the time that the first opening movement of the glumes can be ob- 

 served until they are again tightly closed, seldom requires more than 20 

 minutes." 



More frequent observations were also made at Arlington on 25 heads of 

 wheat between 4 p. m.. May 26, and 10 a. m.. May 80, and on 10 heads between 

 2 p. m., June 1, and 3 p. m., June 5. Data secured at this time are held to indi- 

 cate that the other records possess a high degree of reliability, and that while 

 blooming occurred at most hours of the day it was most intense at rather 

 definite pei'iods. 



Altogether the time of blooming was recorded for 2,977 flowers on 69 heads, 

 1,492 of these flowers blooming at night (from 5 or 6 p. m. to 7 or 8 a. m.), while 

 1,485 bloomed during the day. Of the latter, 764 bloomed before noon. At St. 

 Paul 70 more flowers bloomed at night than during the day, while at Arlington 

 63 more bloomed during the day. The time of blooming appeared to depend to 

 some extent upon the variety, although this is not regarded as the principal 

 factor involved. Two periods of extensive blooming were observed during the 

 day, a morning period from about 7 to 9, and an afternoon period from 2 or 3 

 to 4. A secondary morning period occurred about 11 o'clock. One or more 

 periods are also said to occur at night or probably in the early morning, the 

 exact time not being determined. The blooming period of the flowers on a wheat 

 head ranged from 2 to 7 days, with an average of about 3 days. " The results of 

 these observations should serve to correct the erroneous impression of many 

 that wheat flowers always bloom very early in the morning (apparently ti'ue 

 under some conditions) and that it is necessary to visit such plants at verj'^ 

 early hours in order to secure opening anthers." 



Flowers on a number of heads of several varieties of wheat were emasculated 

 before the pollen matured and left without covering, while flowers on other 

 heads of the same varieties were similarly treated but covered with soft tissue 

 paper at St. Paul, and with paraffined paper bags at Arlington. The varieties 

 employed in Jlinnesota for this work included Kharkov, Red Fife, Haynes Blue- 

 stem, Velvet Chaff, Glyndon Fife, Kubanka, and Arnautka, and at Arlington 

 Fultz, Lancaster, C. I. Nos. 3614, 1733, and 1933, Tennessee Fultz, China, Early 

 Genesee Giant, Acme, and Kanred. At the Minnesota Station kernels were 

 formed by 507 of 1,240 flowers on 70 heads emasculated and left uncovered, 

 while only 2 kernels were formed by 388 flowers emasculated and the heads 

 covered. Where flowers were emasculated, pollinated, and the heads covered, 

 41.7 per cent formed seed. Kernels were formed by 1,103 flowers out of a total 

 of 1,324 on 83 heads emasculated and left imcovered at Arlington. Only 6 

 kernels formed from 642 flowers on 40 heads emasculated and covered, 3 of these 

 kernels being harvested under bags that had been torn. '* When wheat flowers 



