20 GRACE E. COO LEV OX 



shows the habit ol' tlie young plmit (lining gerniination ; a, secil brought above 

 ground ; />, cotyledon ; e, root. 



The cotyledon is here somewhat coiled, as it lies in the endosperm. During 

 growth the re.serve cellulose is dissolved away from the walls, leaving them almost 

 isolated, l)ut active. The method of withdi'awing nourishment from the cells is much 

 as in Ii-is, for the cotyledon does not enlarge so as to fill the seed as in Polygonatnm. 



The endosperm cells retain their protoplasmic contents and act as transfer agents 

 from the cells beyond them. PI. 4, fig. G, shows a seed of Allinm cepa in section, when 

 the resei-ve is almost entirely exhausted, a little only remaining on the walls of the cells 

 in the neighborhood of the mieropyle, at c, in the (iguie. 



All the cells contain protoplasm and oil, .ind the gr(>atei' number have large vac- 

 uoles, the granular protein mattei-s having been willidrawii. 'i'liis seems to be tlie first 

 action of the cells. 



The ct)iled cotyledon contains a great deal of oil in all the cells, and no starch, in 

 these respects differing from Polygonatum and Iris. Starch is found exceptionally in 

 the cotyledon, when the growth has been stunted by accident, as when the root-tip was 

 broken off, or occasionally, when the plant has well established itself and is assimilating 

 vigorously before the reserve material is all exhausted. In other words: starch is some- 

 times formed when the transfer of food to the young plant is cheeked. A little sugar 

 appears in the endosperm and in tlu; cotyledon, but, as in the other seedlings, in 

 very small amounts. PI. 4, (igs. 7 and 8, illustrate the method of solution of tlie 

 reserve from the walls. 



Summari/. From the study of the germination of Polygonatum multifloriim, Tris, 

 and Allium, we gain a general idea of the history of the reserve cellulose during ger- 

 mination. 



1. The method of solution, in all the seeds, [)oints to the tact, elsewhere proved, 

 that the reserve cellulose has been laid down on the original cell walls as a secondary 

 product, not as a constituent part of the original wall. 



2. The solution goes on, while the proto[)lasm of the cell is in an active state. 



3. In all cases where the solution is i^oinii' on, minute u:lobules of oil are found in 

 close contact with the wall. These are of a kind not colored, or only slightly so, with 

 iodine. 



4. Oil is transferred to the cotyledon, and is found either in tlu» outer layers of 

 cells, as in Polygonatum and J lis, or throughout, the mass of the cells, as in Allium. 



5. Starch is only an end product of this activity and does not appear at all in the 

 cotyledon of Allium unless the removal of material is arrested. 



6. . Sugar can only be detected in minutes (piantities during these jirocesses. 



