270 IOWA ACADEMY OF SCIENCE Vol. aXV, 1918 



conditions earlier in the season, produced the largest number of 

 buds and also that the yield in the "off" years of Baldwin apple 

 trees can be materially improved by good cultural methods. 



Mag-ness (24) in 1916 conducted an extensive series of ex- 

 pfnnments to determine the influence of summer pnining- upon 

 the development of fruit Inids in Ore^'on. lie found that head- 

 ing back in eai'ly summer had no influence on the number of 

 fruit '))uds on spurs. l)ut reduced the number of fruit buds formed 

 on the one year wood. Also axillary leaf and fruit buds dif- 

 ferentiated one month later than spur buds on the same tree. 



Black (3) investigated the development of the Baldwin apple 

 from the incipient shoot to the subsequent formation of the 

 fruit. It was found that fniit buds may be anticipated by their 

 position on tiie fruit spur, but are identified with certainty only 

 by dissection. 



Butler (5) has recently published a paper in which he divides 

 branches on which fruit is developed into four classes, fruit 

 branches, sprigs, darts, and spurs. A fruit branch is a leader in 

 which the terminal and axillary buds in the upper two-thirds 

 or thereabouts of its length become flower buds during the season 

 of its development. The sprig is a shoot about a foot in length 

 developing from two year old wo3d. The sprig not infrequently 

 produced a flower bud the year of its formation. The dart is a 

 very short spinelike liranch Avith smooth bark. In some cases 

 it may produce a terminal flower bud the first year l)ut normally 

 it does not produce flowers till the end of three years. The spur 

 is a short, thick, l)rittle branch with nnich wrinkled bark and 

 breaking readily with a smooth fracture. The spur usually de- 

 velops from a bud formed during the previous season, that is, 

 from two year old wood, and requires two season's growth to 

 form a flower l>ud. 



THE PURPOSE OF THE WORK AND ^METHODS EMPLOYED. 



A microscopical study of buds from apple trees subject to 

 different types of soil management should, if extended . over a 

 number of years and including a mntilxu" of varieties, afford 

 some data helpful in .judging the influence of different t.vpes 

 of soil management on the formation and development of fruit 

 buds and thereby be of service in determining the merits of the 

 different tyjies of soil management in relation to the production 

 of fruit. 



