434 THE MICROSCOPE. 



of its structure, much more is possibly observable, and with lower mag- 

 nifying powers than other plants require. Fig. 210, No. 1, is a por- 

 tion of the plant of the natural size. Every knot may produce roots ; 

 but it is remarkable, that they always proceed from the upper surface 

 of the knot, and then turn downwards ; so that it is not peculiar that 

 the first roots also should rise upwards with the plant, and come out of 

 the seed-skin, and then turn downwards. 



The stems and arms are tubular, and entirely covered with smaller 

 tubes ; the circulation can mostly be observed in these : see No. 2. 

 Any ordinary cutting to obtain sections would squeeze the tube flat, 

 and spoil it and the lining ; it is therefore better to avoid this, by 

 laying the Chara on smooth wood, just covered with water ; then, with 

 a sharp knife, make suddenly a number of quick cuts across it, and so 

 obtain the various sections required. Wet a slip of glass, and turn the 

 wood over so as just to touch the water, and the sections will fall 

 from the wood on to the glass, ready for the microscope. 



Mr. Varley gives the following directions for cultivating these plants. 

 He says : 



" The Chara tribe is most abundant in still waters or ponds that 

 never become quite dry ; if found in running water, it is mostly met 

 with out of the current, in holes or side bays, where the stream has 

 little effect, and never on any prominence exposed to the current. 

 If the Chara could bear a current, its fruit would mostly be carried on 

 and be deposited in whorls ; but it sends out from its various joints 

 very long roots into the water, and these would by agitation be 

 destroyed, and then the plant decays ; for although it may grow long 

 before roots are formed, yet when they are produced their destruction 

 involves the death of the plant. In order, therefore, to preserve Chara, 

 every care must be taken to imitate the stillness of the water by never 

 shaking or suddenly turning the vessel. It is also important that the 

 Chara should be disturbed as little as possible ; and if requisite, it must 

 be clone in the most gentle manner, as, for instance, in cutting off a 

 specimen, or causing it to descend in order to keep the summit of the 

 plant below the surface of the water. 



Imitate the freshness of the water by having an extent of the 

 surface, which it is requisite to skim frequently, or suffer to overflow 

 by the addition of more water. These precautions being attended to, 

 a clear bright surface is kept. It is also desirable to change a small 

 portion of the water ; but this should be done without agitation. The 

 best vessels for cultivating this plant are either wide pans holding 

 three or four gallons, or glass jars a foot or more high ; into these the 



