XIV.] STONEWORTS. 435 



matter ; the spiral cells forming its coat acquire a dark 

 colour and hard texture, and the oogonium, detaching itself, 

 falls into the mud. 



After a time the oospore germinates ; a tubular process, 

 like a hypha, protrudes from it through the aperture between 

 the investing cells and almost immediately gives off a branch, 

 which is the first root. The tube elongates, and becomes 

 divided transversely into cells, the protoplasm of which 

 developes chlorophyll. Very soon, the further growth of 

 this pro-embryo is arrested. But one of the cells, which lies 

 at some distance below the free end of the pro-embryo, 

 undergoes budding, and gives rise to a set of leaves (which 

 are not arranged in a whorl), amidst which a bud appears, 

 which has the structure of the terminal bud of the adult 

 Chara stem, and grows up into a new C/^^r^-plant. 



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 

 multiplies sexually by means of the spermatozoids (male 

 elements) and central cells of the oogonia (female elements) ; 

 in which the first product of the germination of the oospore 

 is a simple filament, from which the young Chara is de- 

 veloped by the germination and growth of one cell j 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 COg is decom- 

 posed, so that its nutritive 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 



28—2 



