48 ELEMENTARY BIOLOGY. [CHAP. 



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

 structure is more easily made out. 



[The Characea, 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 Alga, or water- weeds. But no 

 Alga 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 Characece are, in fact, similar to those of the mosses, from 

 which however the Characea differ widely in all other respects.] 



LABORATORY WORK. 



A. NAKED-EYE CHARACTERS. 



Note the slender elongated axis (stem}') the whorled 

 appendages (leaves] ; the nodes and internodes; the shortening 

 of the latter towards the apex of the stem; the rhizoids. 



a. The roots; small; serving chiefly for attachment, 

 the plant getting most of its nutrition, through 

 other parts, from matters dissolved in the water. 



b. The leaves; their sub-divisions (leaflets) ; their 

 form, size, &c. 



c. The spore-fruits and anther idia; their position, 

 size, form, colour. 



Draw a portion including two or three internodes. 



B. HlSTOLOGICAL STRUCTURE. 



a. The stem. 



i. Examine the outside of a fresh internode with a low 

 power, or pocket lens, to see the spirally-arranged 

 cortical cells. 



