276 Principles of Plant Culture. 



440. Cross-Fecundation is accomplished through 

 cross-pollination of the flowers (151) ; i. e., by placing 

 pollen from the anthers of a flower of one of the varie- 

 ties we desire to cross upon the stigma of the other 

 variety. 



441. Preparing the Flower for Crossing. To pre- 

 vent self-pollination (151) in perfect flowering plants 

 (153), we emasculate (e-mas'-cu-late) the flowers, i. e., 

 remove the anthers (143) before the pollen is mature. 

 Prior to maturity, the anthers 



are generally pale in color and 

 nearly smooth on the 

 surface, with no visible 

 pollen, but a little later, 

 the pollen in most 

 plants is visible as a 

 bright yellow dust ad- 



FIG. 171. Case of instruments and 



hering to the anthers. sacks for crossing plants. 

 The anthers may be picked off with the forceps, or 

 the filaments that support them may be clipped off with 

 the points of the scissors. They must generally be re- 

 moved before the petals open (142). The latter may 

 be gently opened with the forceps or needle, or they 

 may be carefully removed. 



In the flowers of certain plants, as the pea, wheat and 

 grape, pollination takes place before the blossom opens, 

 hence in these plants it is necessary to emasculate the 

 flowers very early. 



442. To Prevent Undesired Pollination, the blos- 

 som should be inclosed by tying over it a sack of thin 

 cloth or paper at the time of removing the anthers. 



