16 GRACE E. COOLEY ON 



In PI. 3, fig. 5, A, the condition of the endosperm cells which lie next the cotyledon 

 is seen. Relics of former endosperm cells which have been exhausted of their contents, 

 and pressed upon by the growing cotyledon e, appear at f; and at (j, are loose cells, 

 which are empty but for the large oil drops. 



In B at a, are cells which have been distorted by pressure. 



The contents of the cells, as well as the reserve of the walls, are gradually withdrawn 

 during the encroaching growth of the cotyledon. 



The solution of the reserve from the walls is slow and irreo-ular : sometimes the 

 thickening remains at the corners after the rest of the walls are freed ; sometimes one 

 wall is affected before the others ; and sometimes a large number of cells show a gradual 

 melting away of the substance toward one direction. In the latter case the regular thin- 

 ning of the walls produces a gradual shading of the color which iodine gives. In PL 3, 

 fig. 7, an attempt has been made to represent, by light and shade, the appearance of 

 the reserve cellulose, during its gradual withdrawal from the w\alls. 



PI. 3, fig. 6, illustrates the more irregular solution of the substance. While the 

 solution is going on in the cells, the nucleus often lies in contact with the walls, and 

 these cells, which already have given up their reserve protein matters, contain vacuoles 

 and streaming protoplasm. Granular masses, filled with minute oil globules, cling to 

 the dissolving walls. No starch is visible in the endosperm at any time and only a trace 

 of sugar, if any, is to be detected. PI. 3, fig. 6, is a charactei'istic sketch, showing the 

 oily, granular masses in contact with the walls, whicli are losing their reserve material j 

 at n, is the nucleus. 



A section, which shows the outer layers of the cotyledon and several layers of the 

 endosperm cells, exhibits the phases of solution and absorption. 



First, tlie thickly-filled endosperm cells give up their protein reserve matters and, 

 probably, some oil ; then 'the cells, with the protoplasm in an active state and with large 

 vacuoles, begin to lose the reserve masses of the walls ; and, lastly, tlie protoplasm and 

 the oily matters, which seem to be derived, largely, from the cell walls tliemselves, are 

 withdrawn, and, pressed upon by the cotyledon, the cells collapse. In the cotyledon, on 

 the other hand, appear masses of oil in the outer layer of cells. None is found in the 

 plant outside the seed, and only a little in other cells of the cotyledon. Instead, starch 

 is formed in the starch-formers in the cotyledons in small, but varying amounts, and in 

 large, and more permanent masses, in the bud and young rhizome. 



PI. 3, figs. 6 and 7, show the contents of the cells during the solution and withdrawal 

 of the nourishment from the endosperm. In fig. 7, 1, are cells of the cotyledon, with 

 abundant oil in the outer layer ; at n, the nucleus ; at (j, in the second layer appear the 

 starch-builders. At 2 arc the walls of the collapsed cells pressed upon by the growing 



