1914] SNOW— DIAPHRAGMS OF WATER PLANTS 507 



the functions of diaphragms. Food manufacture undoubtedly 

 takes place, to some extent, in very young diaphragms of Scirpus 

 validus which are close to the exterior. As the stem grows larger 

 and the diaphragms are removed from the exterior by the growth 

 of the outer tissues, they lose their chlorophyll and appear 

 glistening white. 



E. STORAGE 



waste) is stored in diaphragm 



glance (figs. 12 and 



material 



definitely determined. Sauvageau (24-27) notes 

 n various forms of water nlants. and in certain nlaces 



Fig. 10. — Scirpus validus: cross-section of stem at edge of diaphragm: d, dia- 

 phragm cells in position characteristic for cells adjoining a partition; d\ cells of par- 

 tition which have assumed the character of diaphragm cells and are therefore not in 

 the characteristic position; p, partition cells; X175. 



definitely calls the contents tannin. Solereder (31) records the 

 presence of tannin-bearing cells in the diaphragms and the walls of 

 air spaces of the Hydrocharitaceae. He tested with vanillin and 

 concentrated hydrochloric acid, as suggested by Hartwich and 

 Winckel (16) , and obtained the phloroglucin reaction, 

 the same result with HC1 alone, which showed that an aldehyde, 

 similar in action to vanillin, was present. He found in Vallisneria 

 that the contents of certain cells gave the tannin reaction with 



He 



iron, while other cells were filled with a clear oil-like material. 



In material of Scirpus validus killed with chromacetic acid, many 

 brown storage cells appear. An investigation of the chemical 



