26 BULLETIN 75, U. S. DEPARTMENT OF AGRICULTURE. 
EFFECT OF AGE OF FLOWERS UPON SUSCEPTIBILITY TO FERTILIZATION. 
An experiment by Westgate was performed in one of the green- 
houses of the United States Department of Agriculture at Washing- 
ton, D. C., for the purpose of determining whether the age of the 
flower affects its susceptibility to fertilization. A single plant of 
Peruvian alfalfa (F. C. I. No. 60) was used in this experiment. A 
number of young, prime, and old flowers were artificially tripped. 
For the purpose of comparison, a number of flowers at each stage of 
development were marked, but not tripped. Table XVII shows the 
percentage of flowers which produced pods under each method of 
treatment. , 
TaBLE XVII.—Pod setting in relation io age of alfalfa flowers when tripped. 
| Number 




Number | Flowers Flowers | Number! Flowers 
Age. of flowers| of pods bearing not of pods bearing 
tripped. | formed. pods. | tripped. | formed. pods 
Per cent. Per cent 
pVOUNE flOWETS 22-62 oo ne ee ele 15 7 46. 66 18 
TIME SHO WETS boca ee ee 34 17 50. 00 38 0 0 
Oldthowersi fas ys ue ae 81 40 49. 38 89 3 3.37 
A similar experiment, designed to show at what stages of its devel- 
opment an alfalfa flower may become fertilized and also to throw 
some light on the question as to how long it may remain capable of 
fertilization, was conducted at Pullman, Wash., by Evans in 1909. 
All opened and wilted flowers were removed from a number of 
racemes on five different plants inclosed in netting tents. On the 
following day all unopened buds on these racemes were removed, leay- 
ing only those flowers which had opened during the preceding 30 hours. 
As the experiment was carried out in September, when the weather 
was comparatively cool, the flowers remained fresh and open for a 
longer period than would have been the case in warmer weather. A 
number of the flowers on these racemes were tripped each day up to 
the end of seven days, when the tips of some of the petals were begin- 
ning to wilt. The experiment was discontinued at this time because 
the supply of flowers was exhausted. The number of the flowers 
that were tripped and the percentage of tripped flowers which pro- 
duced pods are shown in Table XVIII. 
TaBLeE XVIII.—Results obtained at Pullman, Wash., in tripping alfalfa flowers at 
different intervals after blooming. 
eee of Bare of| Flowers 
Time from opening of flower until tripped. FSS : p ss pens 
: ormed. pods. 
Per cent 
PARY Foote Scone nciek en erate Cee asa een Sam aelon Sas On eee eee ee 103 27.18 
LAS 5 et yn SO ee eae eee tat One Sa Cie ee SC A ee ee ee 69 18 26. 08 
DP OAYS oa. Soma wae ee Cece ele eee nena e ecm cis aur. Cee eet eee ae 96 36 37. 50 
Wa Ek a ee SN ean IC By eee ay Nn ROR he oS ante eS 64 21 $2. 81 
DIGRYS eet nos ee ee on ee hott enn pee smb se een Le ee oe ae oe 7 19 24.05 
"CG FR Pe WE oy ee Se ee ne Vea Ay a ae cme eae Soe Ys EOE 53 28 52. 83 

