HARRIS AND KUCHS : OBSERVATIONS ON POLLINATION. 19 



of material that about an equal number of right- and left-handed 

 (lowers is produced. He also says: "It is also a fact of ob- 

 servation that the Mowers of a cluster on any one branch and 

 opening about the same time are either all right-handed or all 

 left-handed. Any plant, however, if it is at all large, exhibits 

 right- and left-handed flowers in about equal numbers." 



The regularity with which the flowers are divided into the 

 two classes is very striking. Table B shows the condition of 

 ten plants observed at the same time. 



TABLE B. 



Plant 1 7 pistils right-handed, 



" II 6 " " 



III ;.. 8 " 



IV 29 " 



n v 11 " " 



VI.... ....... 10 " 



VII 10 " 



VIII 3 " 



IX 3 " 



X 6 " " 



u 



Total.. 10 93 pistils right-handed, 91 left-handed. 



So in these ten plants the number of right- and left-handed 

 flowers is practically equal. The greatest difference in the 

 number of the two kinds is seen in number X, where forty per 

 cent, are right-handed and sixty per cent, left-handed. 



Considerable care was exercised in determining the number of 

 right- and left-handed flowers opening on the racemes of differ- 

 ent branches at the same time. 



Only those flowers were considered which had opened simul- 

 taneously. In order to effect this, all the flowers were removed 

 from the plant the evening before and note was made of the 

 condition of those opening the next day. 



The following diagram shows the conditions of flowers open- 

 ing on three plants on the morning of August 20, braces indi- 

 cating the branches of the plant, and the straight lines the 

 racemes ; the numbers of right- and left-handed flowers being 

 indicated under the raceme by r and I. (See page 20.) 



From the table, it will be seen that there are on the first plant 

 8 left- and 11 right-handed flowers ; on the second, 24 left- 

 and 27 right-handed ; on the third, 7 left- and 9 right-handed 

 flowers. The numbers of right- and left-handed flowers occur- 

 ring on the divisions a and b of the main branches, A and B, of 

 the three plants, are as follows : 



