118 MISSOURI BOTANICAL GARDEN. 





true. Howard (1906) 



luded 



his study of the ripening persimmon that before ripening 

 the tannin is distributed in the cells of the "loose parenchyma 

 where the tannin cells are located" as well as in the idio- 

 plasts. During ripening the tannin, according to Howard, 

 "becomes condensed in certain specialized cells" (Bigelow, 

 Gore and Howard, 1906, p. 702), and there becomes insol- 



The observed facts in the date (Lloyd, 1907 ), 10 as 



uble. 



do 



date as in the persimmon, either during natural or artificial 

 (Vinson, 1909) ripening, the tannin becomes insoluble, 11 

 and hence the lack of astringency in the fully ripe fruit., in 

 these as in other cases, e. g., the sapodilla, according to 

 Geerlig (1909). What is true of the specialized tannin cells, 

 in this regard, is true also of the remaining tannin cells, those 

 namely in the inner mesocarp and endocarp, and, also, in the 

 integuments, since they are alike tasteless in the ripe fruit. 



The only remaining observations on the date which touch 

 on the following account are the following: Pond (1907) 

 reported finding tannin in the membranes (endocarp) about 

 the seed, and cautioned students of digestion in the germinat- 

 ing date against the introduction of tannin from the integu- 

 ments into the fluids to be tested for reducing sugars. Sachs 

 (1862) discovered tannin diffused through the tissues of the 

 resting embryo, and described the final accumulation of such 

 material in certain parenchyma cells of the seedling. 



Reference has been made to Servattaz' observations on the 

 Eleagnaceae. The tannin, "substances tannoides," he says, 

 occurs in the ovule, in the elongated cells of the nucellus 

 at the base of the embryo-sac and connecting this with the 

 vascular tissue of the raphe. It occurs also in the mid- 

 layer of cells in the external integument. Continuing, he 

 says, "Dans F ovule, ces substances ne prennant pas naissance 

 a la suite de la destruction de Tamidon, car il ne s'y forme 

 jamais de reserves amylacees. Le glucose abonde dan toutes 



10 



Not over his signature. 



11 Mylius (see Dekker, 1906), appears to have made observations to 

 the same effect, but I have not seen his paper. 





