The Bulletin. 



29 



out. It may be that to avoid self-pollination the stamens may ma- 

 ture before the pistils (Proterandnj). On the other hand, the pistils 

 may mature before the pollen is shed (Proterogi/ni/). It may even Ix^ 

 that the pollen of a tree is infertile with the pistillate blooms on the 

 same tree. In all of these cases the tree would be fruitless. This 

 may explain the unproductiveness of some isolated pecan trees. All 

 these problems will doubtless be worked out and the fertilizing char- 

 acteristics of each important variety determined, but it will take 

 rears to do so. In our experimental orchards we have made a start 

 in this direction by putting in solid-block plantings of four promi- 

 nent varieties, namely, Stuart, Frotscher, Van Deman, and Schley. 



Fig. 12. Staminate flowers of the pecan. 



It may be that some of these varieties will not be able to fertilize 

 themselves with their own pollen, and will therefore be unproductive 

 until pollen producers are grafted in. It will require a few years 

 yet to solve all these problems. We have, however, ascertained that 

 the Stuart variety is a wonderfully profuse pollen bearer. A Stuart 

 tree when in bloom can be recognized anywhere in the orchard by its 

 ropes of staminate catkins along the sides of the terminal shoots. 

 The Stuart on account of this habit will undoubtedly be a valuable 

 variety for pollinating sterile sorts. 



Until we know definitely all the fertilizing characteristics of stand- 

 ard varieties of pecans, I would not consider it advisable to make 



