40 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



The squamulae are conspicuous in Zannichellia; their 

 cells are filled with granular protoplasm and the nuclei are 

 large. Their whole aspect is that of secretory cells, and 

 the mucilaginous matter which is found about the younger 

 parts of the plant probably arises from them. 



III. The Roots. 



The roots occur in pairs at the nodes and are slender and 

 unbranched. Their most remarkable peculiarity is the 

 presence of a definite dermatogen extending over the apex, 

 quite distinct from the periblem below it and the calyp- 

 trogen outside. In fig. 126 is shown a longitudinal section 

 of the root-apex, in which the arrangement of the primary 

 tissues can be easily followed. The periblem is referable to 

 a single layer of cells, which divide rapidly by longitudinal 

 walls back of the apex, so that the ground-tissue becomes 

 many layered in the older parts of the root. The epidermis, 

 as already stated, is continuous over the apex, outside of 

 which lies the massive root-cap, whose growth is due to the 

 rapid multiplication of the cells of its inner layer. This 

 type of root is an unusual one, and according to De Bary 

 (1884, p. 9) is known only in two other plants — Ptstia 

 stratiotes and Hydrocharis. Another unusual appearance 

 observed in Zannichellia was the presence of what looked 

 like secretory cells in the epidermis of the root. These 

 are shown in fig. 127. They differ from the neighboring 

 cells in their compressed form, dense contents, and large 

 nuclei. 



IV. The Male Flower. 



Of the two parts into which the staminal primordium is 

 divided, one lies nearer the main axis, and this one becomes 

 the stamen. It is at first scarcely distinguishable in form from 

 its twin structure, the young lateral shoot; but it very soon 

 broadens above, while the base grows but little in diameter 

 and forms the filament, the enlarged end being the young 

 anther. At this stage it resembles curiously in form the 



