CHARACE^. 



283 



including the parts from v to d). This cell is now divided by two oblique walls 

 into three cells, the middle one of which (q) lengthens into a tube (like an inter- 

 node), while the upper and lower ones remain short. Out of the lower cell is 

 afterwards formed a root-producing leafless node (Fig. 203, d, and Fig. 198, d), 

 while the upper one, M'hich lies between the apex of the pro- embryo a b and the 

 elongated cell q becomes the axis of 

 the new generation. It becomes arched 

 on one side outwards, and divides in 

 succession into the cells /, //, ///, and 

 V. Each of the cells /,. //, and /// 

 becomes transformed by divisions into 

 a disc of cells or transitional node, three 

 of which thus stand over one another 

 without intermediate internodes. Their 

 lateral cells grow right and left, and 

 form imperfect leaves of different 

 lengths. The cell which lies outermost 

 (Fig. 203, C, v) now begins to un- 

 dergo a series of divisions, corre- 

 sponding to those of a normal leaf- 

 bearing shoot. It is, in fact, the 

 mother-cell and at the same time the 

 first apical cell of the new generation, i.e. 

 of the sexual leaf-bearing plant which 

 arises from the pro-embryo. The dis- 

 placement indicated in Fig. 203, C, 

 subsequently causes the apex of the 

 pro-embryo to be pushed to one side ; 

 and since this apex has the appearance 

 of a simple leaf uncovered by cortex, 

 the further development of the lateral 

 leaves which spring from the cells /, 

 //, and ///, brings about an appearance 

 as if these different leaves together 

 formed a whorl ; and the bud of the 

 lateral shoot thus comes to stand ap- 

 parently in the centre of this pseudo- 

 whorl (Fig. 203, A). If the structure 



which springs from the germinating spore is now compared with the pro-embry- 

 onic branch, the perfect homology cannot fail to be observed which Pringsheim 

 pointed out in the parts that will be found indicated by the same letters in Figs. 198 

 and 203; but the pro-embryo of the spore has in addition a small node at the 

 opening of the spore from which a rhizoid, sometimes called the primary root 

 of Chara, springs (Fig. 198, w'). 



The Sexual Reproduction of the Characeae results from organs which, in 

 their development and definite form do not, in the present state of our knowledge, 



FIG. 20-^.— Chara fragiUs ; A an entire pro-embryonic branch; 

 i the lowermost colourless cell below the root-node ; rfroot-producing 

 leafless node ; q the long cell proceeding from the middle cell of the 

 bud-rudiment; // apex of the pro-embryo; g the pseudo-whorl 

 of leaves, v the bud of the second generation of the leaf-bearing 

 plant ; B upper part of a young pro-embryonic branch ; z', d, q as 

 before, b apex of the pro-embryo ; /, //, /// the young leaflets of 

 the transitional node, v the bud of the leafy stem ; C still younger 

 pro-embryonic branch ; i, d, q, b as before ; /, //, /// the cells out 

 of which the transitional nodes arise, v apical cell of the stem-bud 

 (after Pringsheim, iSxijo). 



