638 EXPERIMENT STATION EECOKD. 



determining the deciduous or ijersisteut nature of the calyx lobe. A similar 

 study with 56 fruits of the Transcendent crab apple was also made. 



An examination of the data secured with both fruits showed a striking simi- 

 larity in the segregation of the deciduous and persistent factors to that secured 

 in an F2 Mendelian hybrid. The deciduous factor dominated in the pear at 

 the ratio of 1 : 3.7 and in the crab apple at the ratio of 1 : 2.8. Partial evidence 

 is presented to show that the failure of the segregation in the LeConte pear 

 to assume that of a characteristic Fi Mendelian hybrid, i. e., the complete domi- 

 nance of the deciduous factor, may be due to the possibility of either one or 

 both of the supposed parents, Pyrus sinensis and P. communis, carrying both 

 a factor for deciduousness and a factor for persistence. Out of 250 varieties 

 of supposedly pure P. communis studied, 31 per cent sometimes shows a tendency 

 toward deciduous calyx lobes. The author concludes in brief that since the 

 Mendelian ratio is so closely approximated, it is reasonable to consider the 

 LeConte a true hybrid between the species P. communis and P. sinensis. 



Assuming, however, that the LeConte is a mere mutation of P. sinensis, "the 

 data show that there is apparently a mechanism possessed by the somatic cell 

 capable of affording practically the same results and with the same degree of 

 regularity as those afforded by the reduction and fertilization processes incident 

 to bisexual reproduction." It is suggested that this hypothesis may explain 

 the immediate causes of at least some bud variations, and the inquiry as a 

 whole is offered as a contribution to our present limited data on bud variation. 



A bibliography of the cited literature is given. 



The pear as affected by moisture supply, A. F. Barss (Oregon Sta. Bien. 

 Crop Pest and Jiort. Rpt. ID 13-1 Jf, pp. SS-Jf'J, fifjs. .J).— The results for the first 

 two seasons are given of experiments conducted to determine the effect of vary- 

 ing amounts of water upon the growth and fruiting habit of pear trees. 



A test was conducted with 48 uniform dwarf Bartlett pear trees growing in 

 pots under controlled conditions. One lot of pots was kept standing in water in 

 order to insure a continuous supply. Another lot of trees received just as much 

 water as was needed to keep up the supply for the first lot, but the water was 

 applied in twice as frequent applications of one-half the quantity each time. 

 The trees in the third lot received half as much water as for the first two lots. 

 The trees of the fourth lot received just enough water to keep them alive. 



The results for the first year showed no perceptible difference between the 

 different lots of trees in the time required for the trees to leaf out fully. Trees 

 receiving the maximum amount of water developed larger and more brightly 

 colored leaves than the trees receiving half the amount. Trees given the mini- 

 mum amount of water developed small, dull, grayish-green leaves. All of the 

 trees started to form terminal buds at the same time, but these buds grew out 

 again on some of the fully watered trees, thus indicating that large increases 

 in the amount of water above the minimum required by the trees lengthen the 

 growing season. Generally speaking, the amount of wood growth increased 

 with the amount of water supplied, although the difference was not great in 

 the two lots receiving the least amount of water. The lenticels of trees receiv- 

 ing the greatest amount of water were larger and more conspicuous and the 

 growing wood showed more green than on the trees receiving half the amount. 

 When matured and dormant, the wood on the trees receiving the full amount 

 of water was darker and showed less green than the wood on the trees receiving 

 half the amount of water. Late growths put out by the trees receiving the 

 continuous supply of water remained green through the winter. 



During the second season measurements and observations were made at 

 frequent intervals to determine any existing differences in condition of trees, in 



