18 EXPERIMENT STATION RECORD. 



and of many trees examined only a single root of a Whitney crab was found to have 

 started growth from its tip. The roots of the other trees were injured in all degrees, 

 from total destruction to the destruction of the smaller root branches. The author 

 concludes from liis observations that the question as to whether or not the roots of 

 perennial plants resumed growth in spring at their tips depends, in many si)ecies, 

 wholly upon the character of the winter and except in the hardiest species it is prob- 

 able^ tliat there is more or less root killing in the average winter. 



Investigations on tlie root growth of plants, MIjller-Thukgau {Juhresher. 

 Tens. Stdl. u. Schvlr, WddensweU, 1897-98, pp. 79-8:^. — The author conducted a 

 numljer of experiments with gourd and pea seedlings to determine the effect of a 

 mixture of salts upon the growth of the roots. The salt mixture consisted of dibasic 

 phosphate of potash, sulphate of lime, sulphate of magnesia, phosphate of iron,, 

 sodium chlorid, and annnonium nitrate. Different proportions of this combination 

 were added to water cultures in which the plants were grown. The development of 

 the roots was noted from time to time, the growth of the primary and secondary roots 

 being measured and comparisons made with roots grown in distilled water. The 

 concentration of the solution seems to exert a detrimental effect upon root growth, 

 in general the best results being with the weaker solutions. The overfertilization of 

 potted plants with easily soluble nutrient salts will not only impede the transpiration 

 of the plants, but will check the formation of new roots, rendering their growth 

 unsatisfactory. 



Investigation of flower buds, E. 8. Goff ( Wisconsin Sta. Rpt. 1900, pp. 266-285, 

 figs. 32) . — In continuation of the investigation conducted by the author in a previous 

 season (E. S. R., 12, p. 22), the investigations on the origin and development of the 

 flowers of the cherry, plum, apple, and pear have been continued and extended to 

 include the peach and strawberry. The effect of temperature on the development 

 of the flowers was a subject of investigation, and the variation between the appear- 

 ance of the flowers in the two seasons was observed. The author found that the 

 anthers of the cherry and apple did not begin to swell perceptibly until the maxi- 

 mum temperature had reached 70° F. The pollen of the mother cells in the plum 

 and cherry underwent some changes before the temperature reached 50° F. The 

 embryo flowers of the cherry and plum appeared a little earlier than in 1899, while 

 the date of the first appearance of the embryo flowers of apple and pear was not 

 positively determined. In some cases they appeared as early as July, and in others 

 in September. The summer and autumn periods of flower formation may ]jrove dis- 

 tinct, and the late-formed flowers of the ajiple and pear may alone produce a good 

 fruit crop the following season. Side buds, developed on the fruit spurs of apple, 

 formed embryo flowers on several varieties before the middle of October. In the 

 Clyde strawberry, the tirst indication of flower formation appeared Seijtember 20, 

 flowers appearing on the rooted runner plants at practically the same time as upon 

 the parent plant. Experiments in which pear trees were partiall}' defoliated early 

 in July hastened rather than retarded the formation of embryo flowers, and the par- 

 tial defoliation of the fruit spurs of plum and cherries, as embryo flowers were com- 

 mencing to form, did not prevent their formation but slightly reduced their size. 

 The embryo flowers of the peach and strawberry began to be formed with the advent 

 of cool nights in September. Flower buds, although apparently not structurally 

 different from leaf buds, seldom, if ever, revert to leaf buds. In the case of apple 

 buds, they may develop into flowers the flrst, second, or any subsequent season. 

 However, if heavily shaded, flowers may never be formed. In seasons favorable for 

 flower formation many of the buds formed, and nearly all those formed the preceding 

 two seasons that have not already flowered will become flower buds. An excessive 

 apple crop is followed by a light one on account of the supply of reserve buds 

 being exhausted. 



