32 INTRODUCTION. 
In this division the position of the stamens is not regarded as a primary 
character. 
Sus-ciass III. Corolliflore. Monopetalous Exogens. 
Tn the lowest group, the corolla is always absent, making the flower 
Apetalous; and the calyx is not uniformly present. “This character 
is regarded as sufficiently marking the group. 
Sus-ciass IV. Monochlamydee. Apetalous Exogens. 
The object of this classification is to proceed from what are con- 
sidered the most perfectly organized Exogens, to those which are least 
so. Thus all the parts are present and distinct from each other in 
Thalamiflore; other things remaining the same, the stamens adhere 
to the perianth in Calyciflore ; the petals join together in Corolliflore ; 
and in Monochlamydee first the corolla disappears, and then, among the 
most imperfect orders the calyx ceases to be developed. 
38. The class of Enpoeens is not divided by De Candolle into any 
Sub-classes. It will, however, be convenient to consider their orders as 
characterized by the completeness or incompleteness of their flowers. 
The Complete Endogens may be again sub-divided into those with a 
superior, and those with an inferior ovarium. The orders having Incom- 
plete flowers, are separated into those in which a cluster of flowers is 
inclosed in a single large bract, termed a Spathe, which is frequently 
colored (as in the Arum tribe 3) and those i in which the eatin of each 
