386 MANUAL OF NATURAL HISTORY. 



II. SUB-KINGDOM. FLOWERLESS-PLANTS. 



Cryptogamia, Lin. Acotyledones, Juss. Cellu- 

 lares, De Gand. Homorgana, Sckultz. Esexuales, 

 LindL 



1 Class Acrogens (Pseudocotyledonese, Agardh. 



Heteronemea, Fries. 

 Hysterophyta^ 1 ^ 

 Acrobrya (partim), ) 

 Connogense, Lindl. 

 Acrogense, Brongn.} 



2 Thallogens (Acotyledoneee, Agardh. 



Homonomea, Fries. 

 Cryptophyta, Link. 

 Thallo P hyta, ) ^^ 

 Protophyta, ) 

 Amphigense, Brongn. 

 Thallogenae, Lindl.} 



FLO WERING-PLANTS. 



Among Vegetables, Sub-kingdoms cannot be 

 defined or limited with the same precision and ac- 

 curacy as among animals, for the nervous system, 

 of which the different modes of distribution serves 

 so well as the basis of primary divisions in the lat- 

 ter, is totally wanting in the other, nor do they 

 possess any other tissue which can adequately sup- 

 ply its place. Some systematical writers, indeed, 

 discard the separation into Sub-kingdoms altogether, 

 and proceed at once to Classes, Sub-classes, and 

 Orders. But without laying too much stress on 

 such divisions, they seem to be naturally indicated, 



