Rennert : The Phyllodes of Oxvpous fii.iformis 409 



rows of cells, the stomata occurred in definite rows separated from 

 each other by five sterile epidermal rows. Hypoderm was absent. 

 The chlorophyl-cells followed directly upon the epidermis. This 

 tissue was reduced to about three rows, and the palisade character 

 of the first row of cells was not very marked. The endoderm was 

 also less developed. It consisted of only one to three rows of 

 cells. The stellate tissue of the other form was entirely absent 

 here. As a consequence of the meager development of endoderm 

 the fibro-vascular bundles jutted out into the central cavity. The 

 xylem in the bundles was reduced and the position of the resin 

 duct changed. In the normal type it was always to be found out- 

 side of the phloem ; in these phyllodes it was on the other side of 

 the bundle near the xylem. This position of the duct has been 



Fig. 3. Partial cross-section of phyllode, hydrophytic form, X I40- 



pointed out by Van Tieghem as more primitive or juvenile. The 

 diaphragms were composed entirely of thin -walled cells and the 

 anastomosing bundles contained in them were much weaker and, 

 contrary to the habit in the solid phyllode, anastomosed as freely 

 at the center of the septum as about the edge. No trace of glands 

 in the phyllode have been found and there is consequently no 

 general convergence of bundles toward any single point in the 

 margin. 



The phyllodes of the submerged plants possessed in all cases 

 the same structure as those grown under the bell-jar and exhibited 

 an additional modification in their method of propagation. New 

 plants were developed from the nodes of the xerophytic stems 

 which had been developed before the plants were submerged and 

 also in turn from the nodes of plants produced under water. 



The water in which the immersed plants were grown presented 



