322 



MICROSCOPIC FORMS OF VEGETABLE LIFE. 



FIG. 110. 



When removed from the water, they lose all form, and appear 

 like pieces of jelly, without trace of organization ; on immersion, 

 however, the branches quickly resume their former disposition." 

 Their color is for the most part of a brownish-green ; but some- 

 times they are of a reddish or bluish purple. The central axis 

 of each plant is originally composed of a single file of large 

 cylindrical cells laid end to end ; but this is subsequently in- 

 vested by other cells, in the manner to be presently described. 

 It bears, at pretty regular intervals, whorls of short radiating 

 branches, each of them composed of rounded cells arranged in a 

 bead-like row (Fig. 110), and sometimes subdividing again into 

 two, or themselves giving off lateral branches. Each of the pri- 

 mary branches originates in a little protuberance from the primi- 

 tive cell of the central axis, precisely after the manner of the 

 lateral cells of Conferva glomerata ( 198) ; as this protuberance 



increases in size, its cavity is 

 cut off by a septum, so as to 

 render it an independent cell ; 

 and by the continual repetition 

 of the process of duplicative 

 subdivision, this single cell be- 

 comes converted into a beaded 

 filament. Certain of these 

 branches, however, instead of 

 radiating from the main axis, 

 grow downwards upon it, so 

 as to form a closely fitting in- 

 vestment, that seems properly 

 to belong to it. Some of the 

 radiating branches grow out 

 into long transparent points, 

 like those of Chaetophoracese ; 

 and it does not seem by any 

 means improbable, that these, 

 like the " horns" of Vaucheria 

 ( 197), are really antheridia. For within certain cells of other 

 branches, " resting-spores" are formed ; by the agglomeration of 

 which are produced the large dark bodies, that are seen in the 

 midst of the whorls of branches (Fig. 110). 



201. This seems the most appropriate place to consider a group 

 of humble plants, having a peculiar interest for Microscopists, 

 that, namely, of Characece; in which we have a vegetative appa- 

 ratus as simple as that of the Protophytes already described, 

 whilst their reproductive apparatus is even more highly developed 

 than that of the proper Algae. They are for the most part in- 

 habitants of fresh waters, and are found rather in such as are 

 still, than in those which are in motion ; one species, however, 

 may be met with in ditches whose waters are rendered salt by 

 communication with the sea. They may be easily grown for 



Batractospermum monUifarme. 



