KEY TO THE GENERA. 91 



already given, we do not think manuscript names are 

 entitled to any special consideration. 



To supersede the earliest published name, as has 

 been done in the case of several Charophyta, because 

 an earlier MS. name has been vmearthed from some 

 herbarium, is not only contrary to the ' Rules,' but is 

 obviously against the general convenience of botanists, 

 which is after all the main object of nomenclature. 



KEY TO THE GENERA. 



Coronula of oogonium composed of 10 cells in two tiers. 

 Branchlets usually furcate. Kipe oospore terete 

 or laterally compressed . . . NITELLB^. 



Antlieridia apical in the furcations of the branchlets 

 above the oogonia. Ripe oospore laterally com- 

 pressed 1. NiTELLA. 



Antheridia lateral at the furcations of the branchlets. 



Eipe oospore terete .... 2. Tolypella. 



Coronula of oogonium composed of 5 cells in one tier. ' 



Ripe oospore terete .... CHAREJi]. 



Stipulodes absent. Bi'anchlets of 2-3 very long 



segments. Bract-cells 1-2, very long 3. Nitellopsis. 



Stipulodes always present, sometimes rudimentary. 

 Branchlets not furcate of 4 or more segments. 

 Bract-cells normally 4 or more. 



Oogonium normally situated below the antheri- 



dium. Stem ecorticate . . 4. Lampeothamnium. 



Oogonium and antheridium situated side by side. 



Stem corticate. {Not British.) Lychnothamnus. 



Oogonium situated above the antheridium. Stem 



corticate or ecorticate . . . .5. Chaea. 



