106 Wisconsin Academy of Sciences^ Arts^ and Letters. 



It remains to be seen whether tliis classifieation, so simple 

 and logical, is sustained by the consideration of other charac- 

 teristics. • 



Spores and Seeds — 

 Class 1. Has spores only. 



2. Same, 



3. Cotyledons indefinite in number. 



4. Cotyledons definite ; either one or two. 



In all proper systems of classification the indefinite is deemed 

 inferior to the definite, and hence our 3d class, the plants with 

 naked seeds, falls below the whole of class 4. 



Mowers — 



These also show a regular progression through the several 

 classes : 

 Class 1. Flowers obscure or none. 



2. Without proper stamens and pistils. 



3. Without pistils, (stamens only.) 



4. With both stamens and pistils. 



Leaves — 

 Class 1. Leaves none. 



2. With the venation dichotomous. 



3. Venation both dichotomous and parallel. 



4. Yenation parallel and netted. 



Structure — 

 Class 1. Cellular. 



2. Cellular with a few woody fibres. 



3. Cellular with woody fibres ; cells with discs. 



4. With woody and vascular fibres. 



Mode of groioth — 

 Class 1. Irregular ; no distinction of stem and leaf. Thallogens. 



2. A regular ascending axis ; growth at apex. Acrogens. 



3. By external layers. Exogens (in part). 



4. By both internal and external layers. Endogens and 



Exogens 



