CHAP, iv] CHARACE^. 465 



The stems are tubular, and articulated with 

 whorls of membranaceous sheaths, and of 

 slender branches, jointed, and sheathed like the 

 stem at every joint. All the species of Equisetum 

 abound in silicious matter, and particularly the 

 Dutch Rush (£. fiyemale)^ which is used for 

 polishing both wood and metal. The hand- 

 somest species is E. sylvaticum. 



ORDER CCXV.— CHARACE^. 



Aquatic herbs, contained in the genera 

 Nitella and Chara, always growing under w^ater, 

 with slender jointed stems, surrounded at the 

 joints by whorls of tubular leaves or branches, 

 which are either membranaceous and transpa- 

 rent, as in Nitella ; or brittle, and more or less 

 encrusted with carbonate of lime, as in Chara, 

 Stonewort. The organs of reproduction are 

 formed in the axils of the branches, and con- 

 sist of transparent globules, and hard, spiral 

 nuculas, which appear to be formed of twisted 

 leaves, the points of which often form a kind 

 of crest. Young plants are only produced 

 by the nuculas. 



