CLASSIFICATION OF DICOTYLEDONS. 199 



The third order of the Eucydce, the ^Esculince, embraces 

 six families, of which three, the horsechestnuts, etc. (Sapin- 

 dacece),ihe maples (Aceracece), and the milkworts (Polygalacece), 

 have several representatives in the northern United States. 

 Of the first the buckeye (^Esculus) (Fig. 108, J) and the 

 bladder-nut (Staphylea) (Fig. 108, G) are the commonest 

 native genera, while the horsechestnut (^Esculus hippocas- 

 tanum) is everywhere planted. 



The various species of maple (Acer) are familiar examples 

 of the Aceracece (see Fig. 106, A, F). 



The fourth and last order of the Eucydce, the Frangulince, 

 is composed mainly of plants with inconspicuous flowers, the 

 stamens as many as the. petals. Not infrequently they are 

 dioecious, or in some, like the grape, some of the flowers may 

 be unisexual while others are hermaphrodite (i.e. have both 

 stamens and pistil). Among the commoner plants of the 

 order may be mentioned the spindle-tree, or burning-bush, as 

 it is sometimes called (Euonymus) (Fig. 109, A), and the 

 climbing bitter-sweet (Celastrus) (Fig. 109, D), belonging to 

 the family Celastracece ; the holly and black alder, species 

 of Ilex, are examples of the family Aquifoliacece ; the various 

 species of grape (Vitis), the Virginia creeper (Ampelopsis 

 quinquefolia) , and one or two other cultivated species of the 

 latter, represent the vine family (Vitacece or Ampelidce), and 

 the buckthorn (Rhamnus) is the type of the Rhamnacece. 



The fifth group of the Choripetalce, is a small one, comprising 

 but a single order (Tricoccce). The flowers are small and 

 inconspicuous, though sometimes, as in some Euphorbias and 

 the showy Poinsettia of the greenhouses, the leaves or bracts 

 surrounding the inflorescence are conspicuously colored, giving 

 the whole the appearance of a large, showy, single flower. In 

 northern countries the plants are mostly small weeds, of which 

 the various spurges or Euphorbias are the most familiar. 

 These plants (Fig. 109, K) have the small flowers surrounded 

 by a cup-shaped involucre (L, M ) so that the whole inflores- 



