52 KANSAS UNIVERSITY SCIENCE BULLETIN. 



is essentially the same in Nos. 1, 2, and 3, although in this 

 respect there are variations in leaves of the same tree. (Figs. 

 31 to 33.) 



ACORNS. 



The cells of the acorns were approximately the same size, 

 but there was considerable difference in the sizes of the starch 

 grains. The average diameters of the starch grains were as 

 follows : No. 1, .00784 ; No. 2, .006 ; No. 3, .00545 ; No. 4, .00645 

 millimeters. The cells of the acorns were crowded with starch 

 grains in all cases. (Figs. 38 to 41.) 



Iodine, nitric acid and ammonia, and Millon's reagent were 

 used to test for proteins. All three reagents showed more 

 protein in seeds from No. 2 than in the other three, which 

 were about equal in this respect. Ferric chloride indicated 

 about equal amounts of tannin in all, but this was not as 

 abundant in these acorns as in those of most oaks. 



Macerations of the shell and cup of the acorns showed a 

 great variety of stone cells and tracheids, but nothing that 

 would distinguish one from the others. (Figs. 42 to 44.) 



WOOD AND BARK OF THE CURRENT YEAR. 



A cross section of the current year's growth of the stem 

 shows an even gradation in diameter from No. 1 to No. 4. 

 This is mostly due to the differences in thickness of the regions 

 outside of the cambium ring. The growth of the xylem is 

 variable in the same specimen, but the thickness of bark is 

 constant. In No. 1 and No. 3 the cork-cambium produces 

 enough cork in the current year's growth to break up the 

 epidermis, while Nos. 2 and 4 have a smooth epidermis, that 

 of No. 4 persisting for at least three years. The greatest 

 differences were noticeable in the widths of the parenchyma 

 tissues of cortex and pericycle. The bast ring varies in aver- 

 age width as shown in the following measurements : No. 1, 

 .087 mm. ; No. 2, .06 mm. ; No. 3, .0706 mm. ; No. 4, .0435 mm. 

 The average distances between cambium ring and bast ring 

 are: No. 1, .15 mm.; No. 2, .12 mm.; No. 3, .07 mm.; No. 4, 

 .07 mm. The average widths of the parenchyma of cortex 

 are: No. 1, .22 mm.; No. 2, .18 mm.; No. 3, .11 mm.; No. 4, 

 .10 mm. In amount of pith Nos. 1 and 4 were about equal 

 and they had much less than Nos. 2 and 3. The pith cells 

 were about the same size in all. All these variations were im- 

 mediately noticeable under the microscope. (Figs. 53 to 56.) 



