The behavior of the pollen-tube in Houstonia coerulea 



Chester Arthur Mathewson 



The present study was undertaken at the instance of Professor 

 F. E. Lloyd during the past winter, and prosecuted in the labor- 

 atory of Teachers College with his assistance and under his direc- 

 tion. My work, the material for which was collected in the 

 neighborhood of Mt. Holyoke, Mass., in the summer of 1904, has 

 thus far been confined to one species, Houstonia coerulea. 



Methods 



Both young and old flowers were collected and fixed in Flem- 

 ming's fluid, chromo-acetic solution, and alcohol-acetic solution. 

 With the tissue that had been fixed in the first two I used the 

 Flemming triple stain. The tissue fixed in alcohol-acetic solution 

 was stained with iron-alum haematoxylin and Bismarck brown. 

 The latter method has thus far yielded the best results. All the 



sections were cut 10 ti thick. 



Results obtained from allied forms 



In connection with his work on the embryology of the Rubi- 

 aceae, Lloyd has studied the pollen-tube in two genera — Rich- 

 ards oni a and Diodia. Briefly stated, his results show that in 

 Richardsonia pilosa and in Diodia teres the course of the pollen- 

 tube is chiefly intercellular, while in D. virginiana the pollen-tube 

 grows freely in the cavity of the ovary. Since the behavior of 

 the tube is so different in two closely related species of the same 

 genus, and likewise in two closely related genera of the same 

 family, Lloyd agrees with Murbeck that the phenomenon is a 

 matter of physiological meaning only, and disagrees with Treub 

 and Nawaschin in their contention that the intercellular mode of 

 growth is of importance from a phylogenetic point of view. It 

 will be remembered in this connection that Longo, as a result of 

 his studies in the Cucurbitaceae, has come to conclusions similar 

 to those of Lloyd. I may add that my own results seem to add 

 further evidence in support of this view. 



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