EMBRYO, SEED AND CARPEL IN THE DATE. 123 





While generally continuous, and forming a zone of fairly 

 uniform thickness there is, along the line of carpellary fusion, 

 a scattering of the cells. Single cells, or groups of these 

 occur in all the tissue between the inner limit of the carpel, 

 and the outer limit of the zone in question (f. 11). In the 

 condition before pollination, this dipping inward of the tan- 

 nin tissue is not obvious, for the reason that there is little 

 thickness of the carpel here. But with this secondary thick- 

 ening following pollination, the number of tannin cells in- 

 creases within the region of carpellary fusion, as within the 



idioplast zone proper. 



At maturity, the number of tannin idioplasts has increased 



ly, while, also, the size of the elements is also 

 much greater. The largest are upwards of .2 mm. in 

 mdinl measurement, and over .1 mm. in diameter, though 



enormou 



these measurements must 

 erally large size, rather than 



statement 



which varies with the race. I measured the tannin 



a fruit of Deglet Noor. 



be 



these cells. 



examination 



ma 



d of maturation from 



at intervals of two weeks, shows no evidence of the secretion 

 of tannin within the parenchyma adjacent to the idioplasts 



me 



or tannin-like material. If such is the case the evidence 

 would be discoverable since it has been obtained elsewhere 



in the fruit and seed. 



Intercellular Tannin. 16 — A peculiar condition is not infre- 

 quently to be observed, namely, the injection, as it would 

 appear to be, of the intercellular spaces of the idioplasts and 

 adjacent tissues with tannin. 16 I have been unable to fix 

 upon the explanation of this though there is some evidence 



" According to Winckler, extracellular tannin pockets occur, but I 



have been unable to see this paper. 

 i« Howard (1906, p. 570); speaks of this condition, in the persimmon; 



I have recently confirmed his observation. 



