46 ELEMENTARY BIOLOGY. [VI. 



which a bud appears, which has the structure of the terminal 

 bud of the adult Chara stem, and grows up into a new Chara. 



We have then, in Chara, a plant which is acrogenous (or 

 grows at its summit), and which becomes segmented by the 

 development of appendages, at intervals, along an axis; 

 which multiplies, asexually by bulb-like buds, and also multi- 

 plies sexually by means of the antherozooids (male elements) 

 and central cells of the sporangia (female elements) ; in 

 which the first product of the germination of the impregnated 

 ovicell is a hypha-like body, from which the young Chara is 

 developed by the gemmation and growth of one cell ; so that 

 there is a sort of alternation of generations, though the 

 alternating forms are not absolutely distinct from one another. 



Chara flourishes in pond-water under the influence of 

 sunlight, and by the aid of its chlorophyll, so that its nu- 

 tritive processes must be the same as those of Protococcus. 

 From its complete immersion, and the absence of any duct- 

 like, or vascular tissues, it is probable that all parts absorb 

 and assimilate the nutriment contained in the water; and 

 that, except so far as the reproductive organs are concerned, 

 there is a morphological differentiation of organs, unac- 

 companied by a corresponding physiological differentiation. 



Nitella is a rarer plant than Chara, and is simpler in 

 structure, its axis being devoid of the vertical layer. In 

 other respects, however, it is very similar to Chara, and its 

 structure is more easily made out. 



[The Characece, or plants belonging to the genera Chara and 

 Nitella, are found in all parts of the world, and are in many 

 respects closely allied to the Algce, or water-weeds. But no Algce 

 are provided with an axis and appendages possessing a similar 

 structure, or following the same law of growth, nor have any 

 similar reproductive organs. The antherozooids of the Ckaracece 

 are, in fact, similar to those of the mosses, from which however 

 the Characece differ widely in all other respects.] 



