CHAPTER XVIII. 



CLASSIFICATION OF DICOTYLEDONS. 



DIVISION I. Choripetalce. 



NEARLY all of the dicotyledons may be placed in one of two 

 great divisions distinguished by the character of the petals. 

 In the first group, called Choripetalce, the petals are separate, 

 or in some degenerate forms entirely absent. As familiar 

 examples of this group, we may select the buttercup, rose, 

 pink, and many others. 



The second group (Sympetalce, 

 or Gamopetalce) comprises those 

 dicotyledons whose flowers have 

 the petals more or less com- 

 pletely united into a tube. The 

 honeysuckles, mints, huckle- 

 berry, lilac, etc., are familiar 

 representatives of the Sym- 

 petalce, which includes the high- 

 est of all plants. 



The Choripetalce may be di- 

 vided into six groups, including 

 twenty-two orders. The first 

 group is called luliftorce, and 

 contains numerous, familiar 

 plants, mostly trees. In these 

 plants, the flowers are small 

 and inconspicuous, and usually 



crowded into dense catkins, as in willows (Fig. 96) and 

 poplars, or in spikes or heads, as in the lizard-tail (Fig. 97, G), 

 or hop (Fig. 97, J). The individual flowers are very small 



181 



FIG. 96. luliflorsB. A, male; B, 

 female inflorescence of a willow, 

 Salix (Amentacese) , x %. C, a 

 single male flower, x 2. D, a 

 female flower, x 2. E, cross- 

 section of the ovary, x 8. F, an 

 opening fruit. G, single seed with 

 its hairy appendage, x 2. 



