The Sources of Nectar and Pollen 363 



of southern California secrete nectar in abundance only 

 if there is sufficient rainfall while the plants are growing, 

 preparatory to flowering. Because of this fact, the bee- 

 keepers of that region carefully watch the records of rain- 

 fall during the winter to judge as to their prospects for a 

 heavy honey-flow in the summer. The physiology of nec- 

 tar-secretion is so little understood, by beekeepers at any 

 rate, that we do not know the relative importance of tem- 

 perature, humidity, barometric pressure and other environ- 

 mental factors in bringing about abundant secretion. If 

 these influences were more carefully studied, the beekeeper 

 could better forecast his crop and plan his work day by day 

 during the season. As it is, he relies on his unbounded 

 hope of success to carry him through. 



Advantages of swamp sources. 



Since plants which grow in swamps are less subject to 

 changes in available moisture and usually get an abundance, 

 the swamp honey-plants are usually more dependable than 

 those growing in dry soils. In swamp lands, too, the honey- 

 plants are less liable to destruction through agricultural 

 operations and conditions are more likely to remain the same 

 year after year. These facts should be more generally 

 recognized by beekeepers seeking new locations for the es- 

 tablishment of apiaries. The tree sources are usually more 

 dependable than smaller plants. 



Cultivation of plants for nectar. 



It was stated earlier in this chapter that the beekeeper 

 does not cultivate anything especially for his bees. This 

 has been tried several times without profit. However, 

 plants which are nectar-producers and which also have a 

 value in some other respect may often be cultivated with 

 profit to the beekeeper. Alsike clover is an excellent honey- 

 plant and many beekeepers have materially improved their 

 ranges, either by planting this clover as a forage plant or 

 by encouraging neighboring farmers to do so. Buckwheat, 



