50 SCIENCE PRIMERS. [xn. 



84. The principal modifications of the flower de- 

 pend on (a) the absence of one or more of the above 

 whorls, and the form of those that exist ; (b) on the 

 members of each being free or combined ; (c) on 

 the members of one whorl being adherent to those 

 of the one next outside or inside of it ; (d) on the 

 position of each whorl upon the receptacle. Of these 

 modifications, the most obvious is that the ovary is 

 sometimes placed above the calyx (buttercup, Fig. 22), 

 and sometimes apparently below it (snowdrop, daffo- 

 dil, Fig. 37). In the latter case, the appearance is 

 caused either by the ovary being sunk in the top of 

 the flower-stalk, and becoming one body with it, or by 

 the lower part of the calyx adhering to the walls of 

 the ovary; in either case the corolla, disk, and stamens 

 are carried up above the level of the ovary, and are 

 as it were inserted upon it. The rose (Fig. 31) and 

 apple (Fig. 32) are obvious examples of the ovary 

 being sunk in the top of the flower- stalk. 



85. The flowers enumerated below are now to be 

 examined, and the pupil taught to name the organs 

 of each and their uses ; this done, the organs should 

 be described according to their modifications. In 

 doing so, attention should first of all be given to the 

 following points : 



(a) Whether the flower is complete, (Par. 83); 

 if not, which whorls are absent. 



(b) The number of members of each whorl, and 

 whether they are opposite or alternate with the 

 members of the whorl outside it. 



(c) Whether the members of each whorl are free, or 

 combined together, and whether they adhere to those 

 of the whorl outside or inside of them. 



