STONEWOET 281 



various stages of growth. Do you find any, es- 

 pecially the very young oogonia, in which the 

 outer cells have not yet taken the spiral form? 

 Do you also find some in which the spiral cells 

 have become dark-colored and hard, the ripened 

 oospores ? 

 Draw all of the stages found. 



d. The terminal bud. — With scissors cut off the upper 



portions of several plants, put them into one per 

 cent, chromic acid for a day, .then remove one of 

 the terminal buds to a drop of glycerine on a 

 slide ; with dissecting-needles pick away all of the 

 lower parts of the bud, remove these, and put on 

 the cover-glass. While examining the bud under 

 the low power gently tap and press upon the 

 cover so as to push away all of the undeveloped 

 leaves which cover the apex of the stem. How 

 are the leaves arranged in the terminal bud ? Can 

 you trace nodes and internodes in the bud ? At 

 the very tip of the main axis find the apical cell. 

 What is its shape ? Does it have the usual cell 

 contents? How many nuclei does the cell con- 

 tain? Do you find a single cell, the segmental 

 cell, just below the apical cell ? By tracing back 

 from the apex endeavor to see how the nodal and 

 internodal cells are formed, and how the nodal 

 cells eventually give rise to the cortex and to the 

 leaves. 

 Make drawings to illustrate your observations. 



e. The rhizoids. — Examine the nodes and the lower 



end of the main stem of living plants for the floc- 

 culent clusters of root-like appendages, the rhi- 

 zoids. Do you find them on the internodes ? On 



