286 



FLOWERS 



with petals more or less united are said to be sympetalous. 

 (The word signifies petals together.} Flowers with separate 



petals are de- 

 scribed as poly- 

 pe talous. (This 

 word signifies 

 many petals.} 



As to their 

 general form, 

 corollas and 

 calices (plural of 

 calyx) are either 

 regular or irreg- 

 ular. Regular- 

 ity of form is 

 thought to be a 

 more primitive 

 characteristic than irregularity. By a regular corolla is 

 meant one that is radially symmetrical. (See Figure 108.} 

 A wheel is radially symmetri- 

 cal. You can divide it into 

 halves along the line of any 

 radius and the halves will be 

 alike. The same thing is true 

 of regular corollas. Irregular 

 corollas are bilaterally sym- 

 metrical, which means that 

 there is one way and only one 

 way in which they can be 

 divided into halves which are 



alike. (See Figure lop.) Our own bodies, so far as we 

 can tell from their outward appearance, are examples of 



B 



FIG. 106. Dioecious, wind-pollinated flowers of the box 

 elder. A, staminate flowers; each one consists of a 

 group of stamens borne at the end of long, drooping 

 flower stems (pedicels) ; each stamen is composed of a 

 long anther and a very short filament, too short to be 

 seen in the picture. B, pistillate flowers; note the 

 prominent stigmas extended as two branches from each 

 flower ; these flowers have a small perianth. 



FIG. 107. Flowers of Phlox, showing 

 petals united and, by their union, 

 forming a tube. Note that the 

 stamens are attached to the corolla 

 tube. 



