INTRODUCTION. o 



In Smith's 'Flora Britannica ' (1800) they were 

 removed to Class I, Monandiia, sect. Monogynia. 



Louis Richard, in Bonpland, Humboldt and Kunth's 

 ^ Nova genera et species plantarum' (1816), raised the 

 group from generic to ordinal rank, constituting for 

 it the order Gharacese. 



Adanson, in 'Famille des Plantes,' II (1763), had 

 placed the genus Gharava. his Fam. LVI Ara, between 

 Geratophyllon and Fluvialis (Naias), and several other 

 authors associated them with Naiades. They were 

 placed by Lindley and others among the Bryophytes, 

 and by a few authors among the Vascular Cryptogams, 

 but up to recent times the greater number of 

 systematists have regarded them as a group of 

 Algge. 



Strasburger has recently placed them in a separate 

 •class of the Thallophyta, with the following remarks : — 

 p/' The Characese or Charophyta form a group of highly 

 ■organized green Thallophytes sharply isolated from 

 both simpler and higher forms. Their origin must be 

 looked for in the Chlorophycese, but the complicated 

 structure of their sexual organs does not allow of any 

 immediate connection with the oogamous Green Algse. 

 ■On the other hand in some characters they show some 

 approach to the Brown Algae, from which they differ 

 in the pure green colour of the chromatophores. They 

 cannot be regarded as leading towards the Bryophyta 

 although their karyokinetic nuclear division exhibits a 

 great agreement with that of the Archegoniatse." 

 {Fourth English ed. of ' Text-book,' 1912.) 

 fv^.^ Sachs considered them distinct from the Thallo- 

 phytes, elevating the group to a position co-ordinate 

 with his four other great divisions, Thallophyta, 

 Muscinese, Vascular Cryptogams, and Phanerogams, 



