378 Eeport ojf the Horticultural Department of the 



May 18, at 10.30 a. in., the following notes were made on these 

 cultures. 



No. 4. Nearly every grain has germinated and sent out a 

 vigorous pollen tube. The tubes vary in length from about 15 

 to 130,ti or more. The growth is so much tangled that it is 

 impossible to measure each tube. The average length may be 

 estimated at about 80/^. 



No. 5. The percentage of germination is almost as high as in 

 No. 4. The tubes vary in length from 9.5, a to 175 // or more. 

 The growth is matted as noted under No. 4 so that it is impos- 

 sible to get the exact measurement of each tube. 



No. 6. It appears that 50 per ct. of the pollen grains have 

 germinated, but the average length of the tubes is much shorter 

 than either those of No. 4 or No. 5. The tubes vary from about 

 7a to about 86/^ or possibly more. 



No. 7. None has germinated. 



No. 8. None has germinated. 



At G p. m. the same date neither 7 nor 8 had yet shown any 

 germination. The condition of Nos. 4, 5 and 6 was relatively 

 about the same as when the last observation was made. This 

 series of cultures was discarded at 4:40 p. m., May 22. At that 

 time 50 per ct. of the pollen grains had germinated in No. 6, the 

 10 per ct. sugar solution. In No. 7, which contained 5 per ct. 

 Bordeaux mixture B and 5 per ct. sugar solution no germination 

 was found. But in No. 8, which contained 2 per ct. Bordeaux 

 mixture B and 2 per ct. sugar solution a single pollen tube was 

 found. This was 3.36/^ long. One other pollen grain had the 

 appearance of having sent out a tube of about the same length 

 which had disintegrated before it was observed. The other 

 cultures, 4 and 5, so far as could be determined retained about 

 the same relative rank as to growth as was noted before, but 

 the growth was too abundant and the tubes too much matted 

 together to make definite conclusion on this point. It was 

 noticed, however, that some pollen grains in 5 had not yet ger- 

 minated. 



