38 



BOTANY. 



owing to the limy coating. It is fastened to the ground by 

 fine, colorless hairs, or rootlets. 



By making a series of longitudinal sections with a sharp razor through 

 the top of the plant, and magnifying sufficiently, it is found to end in 

 a single, nearly hemispherical cell (Fig. 23, J?, S). This from its posi- 



FIG. 23. A, plant of a stone- wort (Chara), one-half natural size, r, repro- 

 ductive organs. B, longitudinal section through the apex. S, apical cell. 

 x, nodes, y, internodes. C, a young leaf. D, cross section of an internode. 

 E, of a node of a somewhat older leaf. F, G, young sexual organs seen in 

 optical section, o, oogonium. An. antheridium. H, superficial view. G, I, 

 group of filaments containing spermatozoids. J, a small portion of one of 

 these more magnified, showing a spermatozoid in each cell. K, free sperma- 

 tozoids. L, a piece of a leaf with ripe oogonium (o), and antheridium (An.). 

 B, H, x 150. J, K, x 300. I, x 50. L, x 25. 



tion is called the "apical cell," and from it are derived all the tissues of 

 the plant. Segments are cut off from its base, and these divide again into 

 two by a wall parallel to the first. Of the two cells thus formed one 

 undergoes no further division and forms the central cell of an inter- 

 node (y) ; the other divides repeatedly, forming a node or joint (x). 

 As the arrangement of these cells is essentially the same In the 



