THE CALYX AND COROLLA. 



[LESSON 15. 



together takes place in two ways : either parts of the same kind, 

 or parts of different kinds, may be united. The first we may call 

 simply the union, the second the consoli- 

 dation, of parts. 



262. Union or Cohesion with one another 

 of parts of the same sort. We very com- 

 monly find that the calyx or the corolla 

 is a cup or tube, instead of a set of leavesc 

 Take, for example, the flower of the Stra- 

 monium or Thorn-Apple, where both the 

 calyx and the corolla are so (Fig. 199) ; 

 likewise the common Morning-Glory, and 

 the figures 201 to 203, where the leaves 

 of the corolla are united into one piece, 

 but those of the calyx are separate. Now 

 there are numerous cases of real leaves 

 growing together much in the same 

 way, those of the common Thorough- 

 wort, and the upper pairs in Woodbines 

 or Honeysuckles, for example (Fig. 132) ; 

 so that we might expect it to occur in 

 the leaves of the blossom also. And that this is the right view to 

 take of it plainly appears from the transitions everywhere met with 

 in different plants, between a calyx or a corolla of separate pieces 

 and one forming a perfect tube or cup. Figures 200 to 203 show 

 one complete set of such gradations in the corolla, and Fig. 204 to 

 206 another, in short and open corollas. How many leaves or petals 

 each corolla is formed of may be seen by the number of points or 

 tips, or of the notches (called sinuses) which answer to the inter- 

 vals between tLem. 



263. When the parts are united in this way, whether much or 

 little, the corolla is said to be monopetalous, and the calyx mono- 

 sepalous. These terms mean " of one petal," or " of one sepal " ; 

 that is, of one piece. Wherefore, taking the corolla or the calyx 

 as a whole, we say that it is parted when the parts are separate 

 almost to the base, as in Fig. 204 ; cleft or lobed when the notches 

 do not extend below the middle or thereabouts, as in Fig. 205 ; 



FTG. 199. Flower of the common Stramonium ; both the calyx and the corolla with then 

 parts united into a tube. 



