390 MANUAL OF JtfATUKAL HISTOKY. 



named his divisions Thalamiflorce, Calyciflorce, 

 Corolliflorce, and Monochlamydece. In the suc- 

 ceeding pages we shall employ a slight modification 

 of the scheme offered by the learned author of the 

 "Vegetable Kingdom/' who, considering that the 

 parts of fructification are the most important floral 

 organs, has founded his classification on their dis- 

 tribution and relative situation, and accordingly 

 has established four sub-classes, viz., Diclinous, 

 Hypogynous, Perigynous, and Epigynous Exogens. 

 But we consider that the last three, not being equiva- 

 lent in value to the first, must be rejected as sub- 

 classes, and continued merely as inferior divisions. 

 The great distinction among Exogens, being the 

 Hermaphrodite or Unisexual nature of the flowers, 

 indicates two primary sections, the one Diclinous, 

 and the other Monoclinous or bisexual The latter 

 may be satisfactorily arranged according to the 

 position of the stamens into Hypogynous, Perigy- 

 nous, and Epigynous alliances, which principle might 

 possibly be extended to the other sub-class. Ar- 

 ranged therefore in a diagram they appear, thus, in 

 descending series. — 



1. Sub-class Bisexual Exogens ... Monoclines. 



1. Hypogynese. 



2. Perigynese. 



3. Epigynese. 



2. „ Unisexual Exogens DiclineaD. 



I.— CLASS EXOGENS (Exogense). 

 A cellular and a vascular system ; stems with 



