came spherical by the fillinc out cf the furroiiffffs ,thus 

 using the masses of intine on tho inner sides of the 

 furroughs (Fig, 20), Tubes sprout out very soon after 

 being placed in the nutrient gelatine, in fron one to 

 throe hours, and alv/ays arise from the smooth bands. 

 The cultures wore kept at room-temperature and growth 

 was mo:'e luxuriant in the dark. The growth of moulds, 

 etc, , usually disturbed the cultures at tho end of a 

 few days, 



Tlie behavior of the nuclei was not readily ob- 

 served. ?!ethyl-green-acotic-acid was used to kill the 

 pollen tubes. No raore than two nuclei were ever found 

 in a tube. The tubes showed a marked tendency toward 

 the formation of cellulose plugs as shoArn in figure 21. 

 It rarely occurred that part of the contents of the 

 tube was in this way shut off, as the spaces walled off 

 by plugs were mostly empty. In the covirse of about 



