12 



septum, into two cells (Fig. 3 first division of the nodal cell seen 

 from above; Fig. 4 seen from the side, the protoplasmic mass some- 

 what shrunken). 



These cells grow and elon- 

 gate, becoming cylindrical in 

 form, as shown in Fig. 5. 



One of these cells bends 

 down as it lengthens and be- 

 comes a root ; this divides at 

 its base, close to or partly with- 

 in the nucleus, into a complex 



root-node, consisting of several 



Fig. 2. 



nodal eel's, from which several rootlets arise. Fig. 6 represents a section 

 through the primary node "r," the rootlets; "p," the protonema; "pr. r," 



the primary root-node; "sm.," spore membrane. 

 Fig. 7. Front view of node of Ch. coronata; letters as 

 above; "sh.," shell of nucleus. These and all 

 subsequent roots form, by acropetal division, a 

 series of much elongated cells with swollen joints 

 (nodes); these nodes are like two feet, united by 

 their soles in opposite directions, and from the 

 dorsum of the foot, directed toward the point of 

 the root, single rootlets, or bunches of rootlets, 

 arise by a superficial proliferation of cells. Fig. 8 represents a root- 

 node of Nitella megacarpa, Allen, with two young rootlets (drawn 

 from nature, T. F. A. ) 



The other cell, arising by the divis- 

 ion of the primary nodal cell, grows in 

 an ascending direction, opposite to that 

 of the primary root, and elongates into 

 a tube which divides by horizontal fis- 

 sation into three to seven cells; these become filled Math chlorophyll 

 and assume the appearance of a leaf of a Charad. This ceases to 



elongate and is now the 

 protonema (pro-embryo), 

 from which the perfect 

 plant arises in the follow- 

 ing manner : 



The lowest cell of the pro- 

 tonema undergoes -divis- 

 ion near its upper part, 

 by a septum which inter- 



