ALFALFA SEED PRODUCTION". 7 



Honeybees are not nearly so effective as bumblebees, but should not 

 be underrated in this connection, while bees of the genera Andrena 

 and Megachile and various butterflies are also valuable agents in 

 pollinating alfalfa flowers. 



Results are also given showing the seed production of plants whose 

 flowers were artificially tripped in comparison with untreated plants. 

 At Arhngton farm, Virginia, artificial tripping resulted in an increased 

 production of 25.5 per cent, while at Chico, Cal., an increase of 129 

 per cent of pods was obtained. 



Piper,^ in a report of the American Breeders' Association committee 

 on forage crops relating to the breeding of alf aKa, gives an epitome of 

 the answers of members to various subjects of inquiry, five of which 

 relate to pollination. The answers are diverse, some of them based 

 on experiment and careful observations and others more or less 

 expressions of opinion. 



Westgate ^ records that he observed over 500 visits of honeybees 

 to alfalfa flowers, the flower being tripped in but one case. 



Wildermuth ^ records with some doubt that he has seen the butter- 

 fly of the alfalfa caterpillar (Eurymus eurytheme) trip alfalfa flowers. 

 In a personal interview he states that he observed five or six indi- 

 viduals trip the flowers during one season, but has not seen it since, 

 though he has frequently watched the butterflies. This butterfly is 

 very common on alfalfa throughout the Western States. 



It wiU be noted from the brief reviews given that investigators have 

 differed as to their conclusions on several points in connection with 

 the pollination of the alfalfa flower. The most important questions 

 that affect the problem of seed yield left in doubt are the following: 



1. To what extent are the flowers self -fertile? 



2. Is crosE-pollination more effective than self-pollination? 



3. Do alfalfa flowers trip automatically? 



4. Do untripped flowers form pods and seeds? 



5. Is the rupturing of the stigma essential to its becoming receptive? 



6. To what extent do honeybees trip alfalfa flowers? 



In the investigations reported in this paper wiU be found abundant 

 data which go far to clear up the discrepancies in previous work. 



STRUCTURE OF THE ALFALFA FLOWER. 



The structure of the alfalfa flower has been described and illustrated 

 in detail by Hermann Muller and other writers. The most interesting 

 feature is the explosive apparatus which functions to facilitate polli- 

 nation and under proper conditions to favor cross-poUination. The 



'Piper, C. V. Alfalfa and its improvement by breeding. American Breeders' Association, Report, v. 5, 

 1908/09, p. 94-115 1909. 



2Westgate, J. M. Methods of breeding alfalfa by selection. American Breeders' Association, Report, 

 V. 5, 1908/09, p. 147,1909. 



8 Wildermuth, V. L. The alfalfa caterpillar. U. S. Department of Agriculture, Bureau of Entomology, 

 Circular 133, p. 1,1911. 



