i68 



ABOUT HORSETAILS, 



[CHAP. 



.c 



c.c 



FIG. 122. 



The nodal cells give rise to the branches and whorled 

 appendages, and to the organs 

 of reproduction. Fig. 122 is 

 a diagram of a longitudinal 

 section through the plant, and 

 will serve to show the relative 

 size and position of these cells. 

 A.C. shows the large axial cells, 

 separated by N.C., the nodal 

 cells, and invested by C.C., the 

 cortical cells. Fig. 123 is a cross 

 section in which A represents 

 the axial cell,. B the cortical cells. 

 The most remarkable feature in Cliara is what is 

 known as its protoplasmic movements. If a portion 

 of the plant be placed under the microscope, and a 

 low-power objective used, these movements may be 

 seen distinctly. If the focussing be adjusted so as to 

 bring out the large axial cell, and observed carefully 

 for a few seconds, the granules of proto- 

 plasm will be seen slowly, but uninter- 

 ruptedly, to stream up one side of the 

 cell and down the other. Similar move- 

 ments in the protoplasm of cells may be 

 seen in the American Pond-weed {Anackaris alsinas- 

 trum\ Vallisneria spiralis^ and in the hairs of Nettle 

 and Tradescantia. 



From the axils of the whorled appendages Chara 

 produces two orange-coloured bodies the antheridia 

 and sporangia. The sporangium is an oval cell in- 

 vested by five rows of spirally-twisted cortical cells, 

 so arranged as to leave an aperture at the summit. 



FIG. 123. 



