CONTROLLING POLLINATION 73 



Hold the bud between the thumb and forefinger with the keeled side 

 uppermost (B) ; then run a needle along the ridge where the two edges 

 of the standard unite. Bring down one side of the standard, securing 

 it in position with the thumb ; then do the same with one of the wings, 

 which will leave the keel exposed. This must be slit on the exposed side 

 about % in. below the bend in the keel and continuing along until about 

 He hi. from the stigma, which can be seen through the tissue of the keel. 

 Bring down the section of the keel and secure it under the end of the 

 thumb. This will expose the immature stamens, 10 in number. With a 

 fine-pointed pair of forceps seize the filaments of the stamens and pull 

 them out, counting them as they are removed to make certain that none 

 are left (C). Allow the disturbed parts of keel, wings, and standard to 

 assume their original positions as far as possible. Next detach a leaflet 

 from the plant, fold it once, place it over the emasculated flower bud, 

 and secure it in position with a pin or toothpick." 



This prevents drying out. Flowers so treated and pollinated 

 the next morning gave a large percentage of successful crosses. 



FIG. 16. At right, A, scissors useful in removing small organs; B, self-closing 

 forceps; C, forceps commonly used in emasculation with pin attached to the 

 handle; D, scissors for severing large organs. At left, devices used in depollina- 

 tion of flowers; A and B, chip or water bulbs; C, water bulb with valve at bottom 

 provided with celluloid ejector; D, old rubber bulb with glass tube inserted; 

 E, "putty bulb" with attachment to give a small jet of water. (After Babcock 

 and Clausen, 1918. After Oliver, 1910.) 



Depollination with Water. Oliver first used a garden hose in 

 depollinating Grand Rapids lettuce. By cutting down the size 

 of the opening with a smaller piece of rubber tubing a small jet 

 of water was secured. After training this jet for a few seconds on 



