PISTIL. 



80 



placenta is said to be jxirietal. In the otlicr case the dissepi- 

 ments exist in the very early stacjc of the ovary, hut l)y the 

 enlargement of tlie ovary without tlie correspond incr devel. 

 opnient of the dissepiments, tiicy become torn and obliterated 

 with the placenta remaining alone as in tlio Crrastiiun, In 

 ^^« this case it is called a free central placenta. 



^ fiij. lOS. 



It is frequently the case that there are 

 numerous carpels, but they contract no 

 union with e ich otlier as in the Straw- 

 berry j Ranunculus and Ancnomc. 



When the carpels are united as in the Poppi/j Hibiscus dec, 

 they arc said to be Syncari>ous. When they are free as in 

 the Ranunculus. Strawberry, *.^'c., llicy are called apocarpous. 



105. It follows from the assertion, that the pistil consists of a 

 whorl of leaves, immediately superior to those composing the 

 stamens, that they should he alternate w^ith them in their usual 

 position. This is the fact in cases in which we are able to 

 deterniino in regard to it. 



Ill 





If in fig. 110, a, a, a, a> a, represent five stamens, and 

 bj b, as many carpels, it will be observed that the sta- 

 mens occuj)y alternate positions in respect to the car|)els. — 

 This is undoubtedly the fact in all cases which are not altered 

 by non-devclopmeiit or unusual modifications. When the 

 carpels consist of several whorls on the same plane, the in- 

 dividual* of contiguous whorls follow the same law of alter- 

 nation, as is exhibited in fig. Ill, in which a rej)resents 

 the axis, b. b, the whorl contiguous to it, and c. c. the exterior 

 whorl. 



8* 



