FLOWER BUDS OF APPLES 275 



primordia of the carpels appeared whe}i the corolla and stamens 

 had attained a heig'ht of about .10 mm. and the sporogenous 

 tissue was differentiated in the upper anthers when the carpels 

 were from .19 m.m. to .24 mm. in height above the center of the 

 torus. These measurements M"ere found to be practically the 

 same in both varieties of apples and no noticeaible variations doie 

 to the different types of soil managements were observed. Since 

 these measurements were found quite reliable, they were chosen 

 in xjreference to drawing-s as a means of comparison. More than 

 a thousand slides containing median longitudinal sections of as 

 many flower buds were made and the measurements of each bud 

 recorded. 



RESULTS. 

 - The residts obtained from the micrcscopical study of the buds 

 are given in tables I to IV inclusive. In these tables are recorded 

 the measurements of the least and most advanced flowers found 

 in the collections from July 20, 1916, to November 13, 1916. 

 The number in the upper part of the square is the measurement 

 of the least advanced bud in the collection made on the date 

 designated at the left of the table, while the numher at the bot- 

 tom of the square is the measurement of the most advancec^ bud 

 in that collection. The measurement of the floral organ last 

 formed is the one recorded. For example, in the column under 

 plot 1 of clover sod the terminal floAver in the bud showing the 

 least development had a width of onl^- .16 mm., which is much 

 less than the width of the flower at the time the calyx appears, 

 while in the bud most advanced not only the calyx had appeared 

 but the corolla was .02 mm. in heig'ht. In all of the flower buds 

 collected on November 13, the carpels had appeared, and the 

 sets of floral organs were thus complete. The empty squares at 

 the top of Tables I and III, excepting the column under plot 5 

 of Table III, indicate that flower buds were not sufficiently ad- 

 vanced to be told from leaf buds. In a few squares there is 

 only one num'ber in which case only one flower bud was found 

 among the ten collected or all were in practically the same stage 

 of development. The measurements in table I show that on 

 plot 1 of clover sod, the flower buds formed earlier and were 

 more advanced on November 13 than were those on either of 

 the other plots. In all of the other plots, including plot 6. of 

 clover sod, the measurements show that flower buds were not 

 formed until August and hence nearly a month later than on 



