Cross-Breeding and Hybridizing of Wheat. 73 



lowering the stigma is shriveled up as in 14, but the 

 ovary is enlarged and the growth of the grain is begun. 

 At the time of flowering, the anthers, aaa-4 A- also 

 shown in cross section in 5a and in 10, are rapidly 

 pushed up by their filaments, as shown in n>4 B. The 

 opening of the flower is shown in Fig. 10. In this case 

 the actual movements of a flower were observed and 

 recorded from opening to closing. This opening can 

 best be observed in our spring wheats by going out 

 early in the morning and observing the flowers that are 

 nearly ready to open, the anthers breaking open and de- 

 positing the little grains of pollen on the stigmas. These 

 grains of pollen are shown in n, Fig 9, lining the 

 walls of the anther which is there shown in cross sec- 

 tions in 10, Fig. 4, as spherical bodies. In nearly all 

 eases the pollen falls on the stigma of the wheat flower 

 while the anthers are being pushed upward by the fila- 

 ments and before the flower is fully open. In some cases 

 the filaments succeed in pushing the anthers out so that 

 they fall over and are not caught by the two portions of 

 closing chaff, called flowering glume and palea. The 

 breaking open of the anther sacks and the scattering of 

 the pollen grains is illustrated in Fig. 10 at i.i to 16, in- 

 clusive. In some way not readily understood wheat flor- 

 ets nearly always self- fertilize themselves. Vilmorin and 

 Rimpau have estimated that not more than one floret in 

 10,000 is cross-pollinated, and this is nearly a correct 

 statement. It may be that owing to its being accus- 

 tomed to self-pollination the floret's own pollen grows 

 into the stigma more rapidly and more quickly unites 

 with the ovule than pollen from another plant of the 

 same variety, or than pollen from another variety. 



The plan commonly followed in handling wheat 

 spikes is to remove the smaller spikelets at the tip and 

 also at the base of the spike. Then remove the smaller 

 florets at the center and base of the spike, as shown in 

 Fig. n. The remaining are all emasculated by open- 

 ing with small, sharp tweezers, as shown in Fig. 12, 

 and pulling out the three anthers. ., .This is done when the 



