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MISSOURI BOTANICAL GARDEN. 



served, no special tannin cells in the embryo during the em- 

 bryonic or the resting period. In early germination there is 

 according to Sachs' account, a reappearance of tannin, which 

 soon becomes localized. When the extra-seminal portion of 

 the seedling has reached a length of a few cm. the constricted 

 zone of the cotyledon, connecting it with the haustoriurn^ 

 shows a definite tannin reaction. I studied fresh material of 

 the ordinary dates of commerce. Iron chlorid shows, in com- 

 mon with methyl blue, (1) a general reaction throughout all 

 the tissue of the isthmus and (2) a considerable number of 

 special tanniferous cells in the parenchyma in the same 

 region. These react as strongly as the idioplasts. The diam- 

 eter of the neck is one-half that of the cotyledon just outside 

 the seed, so that the areas of the cross-sections are as 1 :4. 

 The reduction of the area does not, however, affect the trans- 

 porting capacity of this part of the cotyledon, since there is 

 no constriction of the vascular tissues. It would appear 

 therefore that these tannin cells are not to be explained by 

 any nutritive relation. It is aplastic tannin, and, as Sachs 

 believed, plays no active role. In the further nutritive phe- 

 nomena seen in the growth of the haustorium or in the diges- 

 tion of the endosperm, there is no evidence of tannin. In 

 the cortex of the seedling, chiefly near the growing end, in 



the region therefore of the hypocotyl, there is observable a 

 slight tannin reaction, but the facts are such as not to lend 

 themselves readily to any explanation. At the close of ger- 

 mination, there are tannin cells distributed throughout the 

 cotyledon, but chiefly in the ventral moiety and in the 

 parenchyma immediately adjacent to the vascular strands. 

 The ventral epidermis contains also a goodly number of 

 tannin cells. The cotyledon is of course moribund at this 

 stage. 



In the first foliage leaf a similar behavior is to be seen 

 save that the tannin appears more especially in the paren- 

 chyma of the dorsal moiety. In the second foliage leaf, 

 before it has yet emerged from the encasing, cylindrical 



first leaf, the tannin appears at first in the parenchyma, in 

 scattered cells lying in the middle zone. There is no diffuse 



