124 PROPAGATION OF PLAKTS. 



the Santana is seven or eight years old, and is planted in 

 the ground in one corner of my greenhouse, and has been 

 cut back several times to keep it within bounds. It is a 

 mass of flowers all the year round, but has never shown a 

 a sign of producing seeds, except as the flowers are arti- 

 ficially fertilized by pollen from some other variety. Its 

 own pollen is impotent for fertilizing its own stigma, as I 

 have proved by repeated experiments, but it is perfectly 

 potent on other varieties. The form of the seed-pods 

 of the Santana is broad top-shaped, the ten to twelve 

 loctilicidal cells are each tipped with a prominent winged 

 terminal point, as shown in figure 48, while the seed- 

 pods of Boule de Neige are slightly smaller, and the 

 cells, instead of widening at the top, are contracted, or 

 more or less rounded inward, as shown in figure 48 at 

 A. Now, to fertilize the stigmas of the Boule de Neige 

 with pollen from the Santana is but a simple opera- 

 tion, requiring only a few minutes for its performance. 

 Twenty flowers in one experiment were thus fertilized, 

 and the result was that five of the seed-pods assumed 

 the form of those of the Santana or male parent, as 

 shown in figure 48, B, the other fifteen retaining the 

 normal form. The plants, however, since raised from 

 the seed show plainly the effect of cross-fertilization. 

 But in reversing this operation, and in fertilizing more 

 than fifty flowers of the Santana with pollen from those 

 of the Boule de Neige, in no instance has there been any 

 very marked change in the normal form of the seed-pods, 

 but I have seldem failed to effect cross-fertilization or 

 obtain fertile seed. The Santana being much the 

 strongest and most vigorous plant of the two operated 

 upon, it is not at all strange that what I presume is the 

 normal form of the seed-vessels should be retained under 

 the circumstances. As a rule the female plant, if 

 equally as vigorous and healthy as the male, will exert the 

 greatest influence upon the offspring, because there are no 



