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SCHOOL AND HOME GARDENS 



Cross-pollination. Petunias afford interesting material 

 for experiments in cross-pollination. Plant two varie- 

 ties of petunias, preferably pure white and red-purple. 

 When the corolla is about to open, cut away a part 

 of it and remove the stamens (as indicated in Fig. 49) 

 and tie a paper bag over it. At the same time place a 

 bag over another one that has not 

 been opened. In a day or two, 

 when the flowers open, remove 

 the bags and with a small brush 

 transfer pollen from the flower 

 that contains stamens to the pistil 

 of the one that has the stamens 

 removed. Replace the bag over 

 the one that has been fertilized, 

 to let the seeds ripen. Transfer 

 pollen from white to red-purple 

 flowers and from red-purple to 

 white. Continue sowing seeds from 

 the cross-pollinated plants for sev- 

 eral seasons, and make a note of 

 the number of red-purple, of white, and of any mixed 

 colors that you obtain. Seeds gathered from red- purple 

 and from white flowers should be sown separately. 

 The plants that are to yield seed should be kept sepa- 

 rate, to prevent further cross-pollination. If you produce 

 plants that bear unusually fine flowers, reproduce them 

 by means of cuttings. 



FIG. 49. Petunias 



a, the corolla closed ; . 6, a 

 part of the corolla opened, 

 showing stamens and pistil ; 

 c, same, with top of stamens 

 removed 



