90 



PISTIL. 



In some cases the receptacle is either convex as in the 

 Strawberry, fig. 112, or concave as in the Rose, fig. 113. In 



11.3 



the former case the outer scries a, a, will be the lowermost 

 whorl, and in the latter, the upper whorl will be in reality, the 

 lowermost in point of development, becoming the most eleva- 

 ted contrary to its true position by the peculiar development 

 of the receptacle, 



106. From the above remarks, it will be easy for the student 

 to reduce to known principles most of the forms of fruit with 

 which he will meet, but there are cases which it is difficult to 

 reduce to the principles laid down. These structures have 

 received various solutions from different Botanists. Some 

 endeavor to reduce them by the above principles, others adopt 

 other principles for explaining them. In the Orohanche, the 

 placentsB instead of being placed at the section formed by the 

 union of the carpels, are placed in pairs on the face of each 

 carpel and at some distance from the margin. There are 

 several anomalies of this character, and in reference to them 

 Lindley remarks, that the position of the placentae with regard 

 to the margin of the carpels is reducible to no certain rule, 

 but depends on specific organization. That a vast majoiity 

 of cases are reducible to the foregoing principles, it is admit- 

 ted by all, and that some cases considered as anomalies are re- 

 ducible to the same principles, we have little doubt. The Oro. 

 hanche it seems to me, may be easily explained by supposing the 

 margin of the carpels inflected on themselves from a union of 

 surface, instead of being directed to the center, when of course, 

 the placentae would be apparently on the fiice of th.elan)ina in- 

 stead of its margin, The close resemblance of buds and 

 ovules, and their supposed and probable identity of origin, is 

 adduced as proof of the placenta not necessarily originating 



