176 STRUCTURAL BOTANY 



duct of its assimilation is deposited in the form of a fatty 

 oil. 



2. EEPRODUCTION 



Vauclieria produces reproductive cells of two kinds 

 asexual and sexual. The asexual reproduction affords a 

 rapid means of propagation, and goes on chiefly when the 

 plant is growing in abundance of water, and generally 

 under conditions that suit it. 



The protoplasm accumu- 

 lates and becomes denser 

 at the end of a branch, 

 c w hich assumes a club-like 

 form. The enlarged end 

 is then separated from the 

 rest of the filament by a 

 transverse septum, for 



FIG. 74. Zoospore of Vauckeria Vauclieria forms cell- walls 

 sessilis. To the left is snown the . . . 



end of a filament, just cut off, by in connection with its repro- 

 thewall(w), to form a zoospor- ^active organs, though not 



angiura. Magnified -25. To the , 



light is a zoospore covered with elsewhere, except in case 



the numerous cilia (c). Magnified f i n i lirv Thp ppll thus 

 95. (After Strasburger.) HJliry. 



formed may be called the 



zoosporangium. The entire contents of the zoosporangium 

 constitute a single zoospore of relatively large size, clothed 

 over its whole surface with numerous short cilia (see 

 Fig.^74). 



The sporangium opens at the apex ; the expulsion of 

 the zoospore is helped by the expansion of mucilage 

 contained in the cell, but depends to a great extent on 

 its own movements. The opening is much narrower 

 than the zoospore, which has to push its way through, 

 -and to change its form in the process (see Fig. 75, A). 



