696 Bulletin 320 



T. H. Dipnall has observed that bees attack swe'et pea flowers. The 

 bee (a yellow-and-white-banded species) alights on the calyx, crawls 

 around it to a certain position, and cuts a hole through the calyx so that 

 it can thrust its proboscis through and suck the nectar at the base of 

 the pod. The reason is not clear why the insect prefers one side of the 

 flower, since the structure is similar on both sides. 



It is to be remembered in this discussion that sweet peas under glass 

 in winter are not visited by bees, but every flower will set seed in sunny 

 weather if the blooms are not kept cut. 



Since the introduction of the waved type there has been much discussion 

 about the difflculty in fixing varieties and the reasons for it. Some growers, 

 having secured what was to all indications a fixed stock, have discovered, 

 after sending it out, that it was not fixed. Some of these growers thought 

 that this occurred only when the novelty was sent to California for working 

 up a large stock of seed, or after it had passed into the hands of the Cali- 

 fornia growers. One of the theories advanced to explain this was that 

 a certain insect in California was responsible for some cross-pollination 

 of flowers. In the trials at this station during the past season no difference 

 was observed between English or American-grown stock, since we had 

 seeds of novelties direct from the originators and our varieties were from 

 the introducers. 



Other growers say that bees visit the flowers, and they believe that 

 crossing takes place in the waved type, which, it is maintained, does not 

 produce normal flowers in that the pistil sometimes projects beyond 

 the keel. It appears that, if this view is correct, the poor seedling of 

 the waved type would not occur, or at least that the worse the fault of 

 the flowers, the greater the crop of seed. Thus, the varieties that seeded 

 freely would become cheap and drive out the others. The writer thinks 

 that the results obtained by the seed growers contradict the theory. It 

 appears that the poor setting of seed may be due to the fact that the pistil 

 may grow out beyond the anthers before the latter are mature, and thus 

 fertilization can be prevented by irregular development of the parts; 

 otherwise, the pollen may be impotent in some varieties, but this does 

 not occur so far as the writer has studied the reports of the sweet pea 

 breeders. The writer did not observe any pistils showing the defect 

 mentioned, but as the season here was very dry the plants did not make 

 an exceptional growth which would be likely to express itself in abnormal 

 flowers exhibiting the pistil. However, it was observed that some vari- 

 eties seeded more freely than others. Most of the varieties were planted 

 here in 191 1 from seeds saved in 19 10 and, knowing those that were 

 fixed the previous year as well as those with rogues of certain colors, 

 it is thought that some light may come on this matter of cross-fertil- 

 ization, if there be any, in the sweet pea. 



