poses a cell between the first and second cells of the protonema; 



this intermediate cell now divides by two septa into three cells ; 



the middle of these three speedily elongates and separates the 



other two. The lower of these two cells 

 becomes a second root-node (as distinguished 

 from the primary root-node which developed 

 directly from the first nodal cell), the upper 



~pr-r. 



Fig. 7. 



becomes a stem node (Fig. 17, "rn." a root- 

 node, "s" the stem-node). The lower cell, 

 which is to develop into a root-node, under- 

 goes repeated fissation by vertical septa, as il- 

 lustrated by Figs. 9 to 12 (Fig. 12 representing 

 a fully developed root-node with "a," "c," "d,"' protruding rootlets). 

 This completes the development of the roots. 

 From the upper of the two cells a stem 

 node develops as follows : This cell divides by 

 a septum into two nearly equal halves (Fig. 13). 

 In each half peripheral cells arise, first on one 

 side, then on the other (Figs. 14 and 15), until a 

 circle of cells is completed, inclosing two me- 

 dian cells. The formation of this node is simi- 

 lar to that of all nodal forma- 

 tions in the fully developed 

 plant. The first cell now 

 throws off another peripheral 

 cell, which divides, by a verti- 

 cal septum, into two cells, 

 which stand for the nodal cells 

 of the new stem (" n," Figs. 15 

 and 1 6). In Fig. 16 a side view 

 of the node "v" is the vege- 

 tation cell, growing upward and elongating into the first stem (cell) of 

 the perfect plant; the two nodal cells, "n," remain as small nodules 

 on the side of the node, or develop into accessory leaflets (stipulse). 

 The other peripheral cells of this 

 stem-node develop into very simple 

 leaves of unequal length ; these 

 leaves always remain at the lowest 

 stage ; they never develop nodes 

 nor bear fruit. The extension of the original protonema often exceeds 

 the length of the leaves of this provisional verticil and may easily be 

 mistaken for one of them, especially as it is crowded out of its nor- 



g. 



Fig. 9. 



Fig. 10. 



