156 



flowers may yield impotent pollen. This may readily be deter- 

 mined by appropriate germination tests and by microscopic exami- 

 nation. But most varieties probably do produce good or viable 

 pollen. 



There is much evidence that the flower behavior of chestnuts 

 has an intimate relation to proper pollination and is perhaps re- 

 sponsible for the self-fruitlessness so frequently observed. The 

 best statement regarding the flowers and their development which 

 the writer has seen is that of G. Harold Powell, published in the 

 Eleventh Annual Report of the Delaware Agricultural Experi- 

 ment Station for the year 1899. The statements there made re- 

 garding the flowers of chestnuts may be quoted in full. 



Figure i. Beloiu. The several bushels of chcslnut burs here shown 

 fell from a large tree standing at one side and with its branches above the 

 driveway in which the burs were jiiled. The large crop of burs seemed to 

 promise a harvest of nuts. 



Above. Rarely did a bur yield a nut containing a meat. The total har- 

 vest was a small handful of good nuts. 



Evidently many varieties f)f chestnuts arc self-fruitless. Cross-])olli- 

 nation seems to be necessary for adequate yields of good nuts. 



" The Blossoms. The chestnut is monoecious, that is, the 

 male and female flowers are separate on the same tree. 

 Young, vigorous-growing trees frequently produce male 

 flowers only, and after their excessive vegetative vigor ceases 

 and the trees become older, the female flowers develop. The 

 staminate flowers are borne in long, slender catkins, and are 

 much more ninnerous than the pistillate llowers. The jiistil- 

 late flowers are clustered at the base of a long catkin, on the 

 distal end of which the staminate flowers open later in the 

 season, the catkin aborting down to the little female blossoms. 



"The pistillate flowers are probably fertilized by both sets 

 of staminate blossoms, the early ones fertilizing the early 

 opening blossoms, and the later ones furnishing the pollen for 

 those that are retarded. Thomas Meehan tells me that he 

 thinks the pollen from the late staminate blossoms performs 

 the function of fertilization, and thai the great show of stami- 

 nate catkins is a waste of energy, in the American chestnut. 

 Tn both Euroiiean and Japanese varieties, I have noticed that 

 most of the ])istils are receptive while the early staminate 

 flowers are in bloom." 



b'roni this de.Ncriplion for clK'Slinits in general, it ap])cars that 

 certain catkins bear only staminate flowers which mature rather 

 early. Other catkins bear both pistillate and staminate flowers 



